PHYS Straighterline
How much work is done by a 50 N m torque that rotates a wheel through one revolution?
314 J
The work done by a variable force F of the form F = kx where x varies from x0 to x1 where x0 = 0 is given by which of the following?
(1/2) kx12
A binary star system consists of a star of mass M and a second star of mass 3M. They orbit in circular paths around their common center of mass with radii ra and rb, respectively (see the diagram). Which expression below is correct for the speed of the larger star, vb?
(GMrb)1/2 / (ra + rb)
An automobile of mass 900 kg is moving at a speed of 12.5 m/s when it encounters a hill. At the bottom of the hill the car speed increases to 14.6 m/s. If the elevation of the hill is 15.3 m, how much work did the brakes do while going down the hill?
-1.09x105 J
A video game includes an asteroid that is programmed to move in a straight line across a 17-inch monitor according the equation x=6.5t-2.3t^3, where x is in inches and t is in seconds. At some point during the trip across the screen, the asteroid is at rest. What is the asteroid's acceleration at this point?
-13 in/s^2
A child has only one pea left on her plate. Playing with her food she finds that if she tilts the plate at an angle of 15 degrees or more, the pea starts to slide down. What is the coefficient of static friction between the pea and the plate?
0.27
Which of the following is the magnitude of torque resulting from a 2.4 N force applied 17 cm from the point of rotation if the force is applied at a 45 degree angle to the displacement vector?
0.29 N m
Torque is given by the formula.... Which of the following is the magnitude of torque resulting from a 2.4 N force applied 17 cm from the point of rotation, if the force is applied perpendicular to the displacement vector?
0.41 N m
A brass cube, 10 cm on a side, is raised in temperature by 200oC. The coefficient of volume expansion of brass is 57 x 10-6/Co. By what percentage does its volume increase?
1.14%
The distance along both the axes, as shown in the drawing below, are in meters. Which of the following is the resultant gravitational force vector acting on the 100 kg mass at the origin of the diagram?
1.3 and -85
An ideal gas with internal energy U at 200oC is heated to 400oC. Its internal energy will be what?
1.4 U
A jug of tea is cooled down by putting it in ice. The mass of the tea is 1.8 kg and is initially at 80oC. How many kg of ice, initially at 0oC, are required to bring the mixture to 10oC? (Lf = 3.34 x 105 J/kg, specific heat of water is 4186 J/(kg Co).)
1.4 kg
What is the angular velocity of the Earth as it rotates about the Sun? The distance from the Earth to the Sun is 1.50 × 1011 m.
1.99
A 0.200 kg dart is fired horizontally at a speed of 2.75 m / s when it hits a 0.700 kg block of wood suspended by a string. The nose of the dart sticks into 0.00210 m the wood. Together the dart and block swing upwards from a height of 0.0500 m above a table to 0.128 m above the table. Which of the following is the average force the dart applies to the block during impact?
32.4 N
One person drops a ball from rest 10 m above the ground. Simultaneously, a second person throws a ball down with an initial downward velocity of 3 m / s. If the two balls hit the ground at the same time, what total vertical distance did the second ball fall?
14.3 meters
At which of the following speeds would you have to throw a beanbag if you wanted it to reach a maximum height of 8 m above the point you released the beanbag? Assume you throw it at a 60° angle with respect to the horizontal.
14.5
Given the vectors C = 1.5i + 6.2j and D = 4.4i + 7.3j, calculate the magnitude of their vector product.
16.3
A rock is thrown vertically up into the air. It reaches a maximum height 15 m above the point where it was released. What is its initial velocity?
17
The volume of a fixed mass of an ideal gas is doubled while the temperature is increased from 100 K to 400 K. What is the final pressure in terms of its initial pressure Pi?
2 Pi
Your cat chases a spider across the floor. Its position is a function of time is r + (1.2m/s)ti + (0.7m + (0.5m/s2)t2)j, where the origin is the southwest corner of the floor. Find the average speed of the cat between t = 0.0s and t = 4.0s
2.3 m/s
Ron
2.5x10-13
A snow skier is at the top of mountain trying to decide which ski run to take since they all have different slopes. He wants to slide down with a constant speed. If the coefficient of kinetic friction between his skis and the snow is 0.05, find the angle (or slope) of the path he should choose.
2.8 degrees
Two scientists... how fast must the other scientists plane travel relative to the ground so that the difference in time intervals predicted by relativity can be detected?
2.9 x 10^6
A 0.400 kg iron horseshoe that is initially at 500oC is dropped into a bucket containing 20 kg of water at 22oC. What is the final equilibrium temperature? Neglect any heat transfer to or from the surroundings. The specific heat of iron is 452 J/(kg Co).
23.0oC
A roller coaster has eight cars, each of mass of 95.0 kg. The ride begins 47.5 m above the ground. Which of the following is the speed of the train as it encounters a section of track that is 30.0 m below the ride's starting point? Assume that the train starts from rest.
24.3
An experimental new ride at an amusement park begins by spinning patrons about a circle of radius R with constant speed v. At some point during the ride the speed doubles and the spokes extend, doubling the radius. After this occurs, what is the acceleration of the patrons in terms of the original acceleration, a ?
2a
Which of the following is not a vector?
2kg of mass under a table
When a certain jet engine is running, 11,500 W of power goes into its deafening roar. How far away from this engine can you stand before the sound level you experience crosses the "threshold of pain," 120 dB? Assume that the engine generates sound equally in all directions.
30 m
Using Kepler's third law of planetary motion, how many times larger is the average radius of Neptune's orbit if it takes 164 Earth-years to orbit the Sun? Approximate each orbit as being circular.
30 times larger
A spider is accelerating downward on a single strand of silk. Which of the following must be true?
T − mg = −ma
A child is guiding a toy airplane attached to a guide wire around in a circle. The plane circles with a period T. If the child pulls in the guide wire to half the original radius, while simultaneously adjusting the speed so that the period T remains constant, how has the centripetal acceleration changed?
The acceleration decreases by 2.
Which of the following is correct concerning the centripetal acceleration of an object in uniform circular motion?
The centripetal acceleration is directed radially inward.
Sally in St. Louis, MO gets a call on her cellular phone from Cindy in Cincinnati, OH, who invites her to go to a Reds baseball game. The cellular signal travels through a satellite that is in geosynchronous orbit exactly half way between St. Louis and Cincinnati at a height of 36,000 km above the Earth's surface. The next day, Sally gets in her car and drives to Cincinnati where she watches the game. There are approximately 600 km between St. Louis and Cincinnati. What is the difference between Sally's displacement and the displacement of the cellular signal? (Assume that St. Louis and Cincinnati are at the same height above sea level.)
The displacement of the cellular signal is the opposite of Sally's displacement.
Assume that when the brakes are applied a constant frictional force is exerted on the wheels of a car. Which of the following is correct?
The distance the car travels before coming to rest is proportional to the square of the speed of the car just before the brakes are applied.
A rocket leaves the surface of the Earth and flies to a distance of one Earth radius above the surface of the Earth. What happens to both the gravitational force and potential energy of the rocket?
The force decreases by factor of 4. The potential energy increases by factor of 2.
A humming bird is flying... At t = 3.0 s is the humming bird speeding up, slowing down or is its speed constant? Also, is the bird turning?
The humming bird is speeding up and turning.
When turning around a circle, a car is subject to a continuous force, but its speed does not necessarily change. Why is this true?
The speed is not changing, but the direction is.
Consider a particle of mass m in uniform circular motion on which the centripetal force is increased. Which of the following is correct?
The tangential speed will increase and / or the radius will decrease.
Which of the following is a correct statement concerning the velocity of a particle in uniform circular motion?
The velocity is constantly changing directions.
How are seconds defined?
They are based on the time it take cesium atoms to vibrate.
Why is ixj = 0?
They are separated by 90 degrees.
Suppose you weigh an object and the reading you get from the scale is 0.0070 kg. How many significant digits does your measurement have?
Two
Which one of the following statements concerning the derivation or usage of Bernoulli's equation is false?
Vertical distances are always measured relative to the lowest point within the fluid.
Which of the following is not a unit of power?
Watt / second
When a small car pulls a trailer for a move, which of the following explains why the trailer moves?
While the force of the trailer on the car is equal and opposite to the force of the car on the trailer, the total of all forces acting on the car are unbalanced.
If two objects that orbit each other collapse into a single spinning object, will the angular momentum be conserved?
Yes, because they are part of the same system
A 3.5 kg object is placed on a frictionless incline as shown in the diagram. The object's initial velocity is zero and it starts to slide down the incline. What are the acceleration and final velocity of the object when it reaches the ground level?
a = 5.6 m / s2 v = 8.9 m / s
If you are observing a moving object, which of the following would alter your measurement of the magnitude of the object's velocity?
a moving reference frame
From the following choices select the one that is not required for making quantitative statements about the world.
a regional unit system
Which of the following results from (AxB)xC, where A, B, and C are all vectors?
a vector
A wave pulse is incident on the boundary between a heavy rope and a lighter cable, as shown. Which of the following diagrams correctly illustrates the system a few moments later?
a) little up bump, big up bump
For the given velocity-time graph, select the corresponding position-time graph.
a. (gradual slope)
Which of the following is an example of scalar product?
arrow A dot arrow B
Two physics students are measuring the velocity of a car on an air track. For both of the students measure the same value for the velocity, they must _____________.
be in the same reference frame
Which is not an mks unit?
centimeter
When an ice skater pulls in her arms, she speeds up and her kinetic energy increases. Where does this energy come from?
chemical energy
The derivation of Bernoulli's equation relies on _______________.
conservation of energy
Which of the following applies to the tangential velocity v of uniform circular motion?
constant speed but not constant velocity
Which graph best illustrates the following description of motion? A car starts at rest, accelerates at a constant rate until it cruises at a constant speed, and then brakes at a constant rate until it is moving at a constant, very slow speed.
d (hill looking one)
A power company charges its customers for electricity based upon which one of the following?
energy
Bernoulli's equation does not include the effects of______________.
friction
A small mass is placed on a turntable that is rotating at 45 rpm. The centripetal acceleration is ____________.
greater when the mass is farther from the center of the circle
In general, the frictional force ____________.
is proportional to the normal force
If the radius of a pipe carrying water is doubled, the velocity of the water___________.
is quartered
You are sparring in karate class. Your opponent, standing directly in front of you, throws a punch straight into your chest. What stance will best allow you to take this punch without losing your balance?
left forward
A sinusoidal wave is traveling down a rope. In each of the following diagrams, a small piece of the rope is shaded. All the pieces have the same length. In which diagram does the shaded piece of rope have the least amount of energy? Neglect gravitational potential energy
little blue at top middle
Consider the function q=1/4ct^3, where c is in units of m/s, and t is in units of seconds (s). What are the units of the function q?
m x s^2
A person with mass m is on a ride in an amusement park... Ignoring air resistance, the normal force must be equal to ______.
ma
From the following select a "derived unit" in the metric system.
meter / second
In simple harmonic motion, the velocity is greatest when the object has the ____________.
minimum accleration
A pulse of amplitude A travels on a string toward the end of the string that is free to move vertically. The tension at the free end is maintained by tying the string to a ring of negligible mass that is free to slide vertically on a frictionless post. Assume that there is no transmission of the pulse into the pole and that the amplitude is in the upward direction from the equilibrium position. Which of the following characteristics of the reflected pulse is correct?
non-inverted with amplitude A
In which of the following high speed collisions does the car experience a smaller force than the other object participating in the collision?
none of the other choices
In an isolated system, momentum is conserved. Which of the following is not equivalent to the momentum conservation law?
p = 0
A point mass m is hung on an ideal, massless rod of length z. A torque of magnitude r is applied to the system about P, displacing it as shown. What is the horizontal displacement L of the mass from vertical?
r/mg
If the radius of a pipe carrying water is doubled, the volume flow rate of the water____________.
remains the same
Which is the standard unit of time in the metric system?
second
A constant force is applied to an object that starts from rest. Which of the following best describes its acceleration as a function of time?
straight horizontal line
Two events, A and B, have spacetime coordinates... The fact that "simultaneity is relative" means
t1 does not equal t2
Heat is applied to an ice-water mixture to melt the ice. In this process, __________________.
the internal energy increases
The natural direction of the net heat flow between two reservoirs depends on
their temperatures
The position of an object along the x-axis is described by the formula x = 2t 3 − 4t. Which of the following are the correct formulas for the velocity and acceleration of the object?
v = 6t 2 − 4, a = 12t
Which of the following is not a frictional force between solids?
viscosity
An airplane has an initial velocity with respect to the ground of 200 mph in an eastward direction. A strong wind begins to blow with a velocity of 80 mph from north to south. What are the x-and y-components of the total velocity of the plane when the wind is taken into account? Let north be the positive y-direction and east be the positive x-direction.
vx = +200 mph vy = −80 mph
If the position on vector of an object is r(t)=4ti-3j, what are the instantaneous velocity vector components at t=1s?
vx = 8 m / s, vy = 0 m / s
Which of the following is the general solution of a damped oscillating system?
x(t)= Ae ^-bt/2m cos (wt +o)
Two identical masses are connected by a thin rod, as shown. About which point is the moment of inertia of the system the smallest?
x3
What is the scalar product of two perpendicular vectors?
zero
A boat pulls a water skier who weighs 127 lbs at a constant speed. The tension in the ski rope is 125 N. The skier makes a run that is 0.7 km down a long straight river. What is the work done by the water skier on the boat?
−8.75 × 104 N • m
A large asteroid is heading directly towards Earth on a collision course... If the missile travels at a speed of 0.800c, what should the timer be set at so that the explosive detonates just as the missile impacts the asteroid? Ignore gravitational effects.
334 s
The temperature of a fixed mass of gas drops from 127oC to 27oC under constant pressure. Find the ratio of the new volume to the original volume.
3:4
Given the vectors C = 2i + 7j and D = 14i + 38j, find the angle between them.
4 degrees
Using the conversion factor between kilograms and pounds, 1 kg = 2.205 lb, calculate how many pounds are in 2.00 kg.
4.41 lb
A bicyclist is heading east along a straight bike path. As the path crosses into a state park, it turns from dirt to pavement and the biker accelerates at a constant rate of 1.2 m / s2. At time t = 0 the bicyclist is 2.0 m east of the state park line and is going at a speed of 3.0 m / s. Where is the cyclist when his velocity is 10.0 m / s?
40
A meterstick is moving at a speed of 0.73c relative to you. In its own frame, the meterstick is tilted at an angle of 45 degrees. At what angle is it titled in your frame?
45 degrees
What is the internal energy of 7.91 x 1022 gas molecules at a temperature of 300 K?
492 J
If the x-component of a vector is 3 and the y-component is 4, what is the magnitude of the vector?
5
A car of mass 1365kg... wheels?
5%
The position as a function of time for your dog as it chases a ball across the yard is r = (0.9m + (0.7m/s^2)t^2) i + (4.6m/s)tj, where the origin is the northeast corner of the yard. Find the average speed of the dog between t=0.0s and t=3.0s.
5.1 m/s
An ordinary glass is filled to the brim with 350 cm3 of water at 100oC. If the temperature decreased to 20oC, how much water could be added to the glass? Neglect the volume expansion of the glass. (β water = 207 x 10-6/Co)
5.80 cm3
Suppose that 80 L of a gas has a gauge pressure of 2 atm and a temperature of 300 K. How many molecules are there in the gas? (1 atm = 1.013 x 105 Pa , R = 8.314 J/(mol K), NA = 6.022 x 1023)
5.87 x 1024
A mass of 4.3 kg is accelerated to 6.0 m / s2 when a force of magnitude F is applied to it. If the same force is applied to a mass of 0.5 kg, what is the acceleration of this mass?
51.6 m/s2
As a copper wire is heated, its length increases by 1/10 of 1%. What is the change in temperature of the wire? (αcopper = 16.6 x 10-6/Co)
60.2oC
The radius of the Moon is known to be 1.7 × 106 m. Astronauts who walked on the Moon measured the time it takes an object to fall 1 m on the Moon to be about 1.1 s. Using this information, which of the following is the mass of the Moon?
7.1 × 10 22 kg
The exhaust temperature of a Carnot heat engine is 573 K. What is the intake temperature if the efficiency of the engine is 30%?
819 K
If a spring is compressed 2.0 cm from its equilibrium position and then compressed an additional 4.0 cm, how much more work is done in the second compression than in the first?
8x
Which of the following pairs of vectors have the same direction?
A) A 3i + 2j/ B 6i + 4j
Because the energy in SHM alternates between kinetic and potential, at some position x, the kinetic energy must be equal to the potential energy. For the general case, an object undergoing SHM with an amplitude A, which of the following is this position?
A/root of 2
Alex sits in a vehicle moving at a constant 43 mph. She watches a gazelle leap into motion, accelerating rapidly to full speed. Harry watches the same gazelle from a tree. Which of the following statements is true?
Alex and Harry both measure the same acceleration for the gazelle.
Recent data suggest that as it continues on its course, the voyager spacecraft is, in fact, slowing down more than is predicted by the gravitational pull of the Sun. Which of the following presents the best explanation?
Another, unknown force is acting on the spacecraft.
Which of the following statements is true for any completely enclosed ideal fluid?
Any change in pressure is transmitted equally to all points in the fluid.
Given the vector A as shown in the figure, select the choice that gives the vector's correct description in component form.
Ax = Acos0 Ay = Asin0
Given the vectors A = 6i + 3j and B = i + 9j, find their scalar product AxB.
AxB=33
A lift force is exerted on an airplane wing as a result of _______________.
Bernoulli's
Constantly accelerated motion
Curvy graph
Which of the following is the general definition of impulse ?
I = squiqqle E Fdt
What happens to a given mass of water when it is cooled from 8oC to 4oC?
It contracts.
This hourglass-shaped object is hung from a pivot point (round dot). Its center of gravity is marked by a cross. If the object is free to rotate, what does it do?
It does not move.
What determines an object's moment of inertia?
Its mass distribution
The internal energy of an ideal gas depends on what?
Its temperature
In space, far away from any planets, which of the following spacecraft requires the greatest force to accelerate?
Megaship, the large and powerful, with a mass of 10 million kg
In an inertial reference frame __________.
Newton's three laws are apparent and valid
A Ferris wheel having a radius of 8 m has a velocity of 8 m / s. Is there a danger of the riders flying off?
No the Ferris wheel is not moving too fast.
Which of the following best describes the relationship between two systems in thermal equilibrium?
None
Where does the concept of moment of inertia come from?
Rotational kinetic energy
Why does an ice skater's angular velocity increase when she pulls in her arms during a spin?
She reduces her moment of inertia.
A binary star system consists of two identical stars moving in circular orbits around the system's center of mass (see the diagram). The mass of each star is M and the radius of the orbit is R. Which expression correctly gives the orbital speed for one of the stars?
(GM/4R)1/2
An oscillating mass is connected to a horizontal spring with a spring constant k. The force that the spring exerts on the mass is described by __________.
−kx
A spaceship is in space and currently at rest. The directive is given to accelerate from rest to a speed of 2.90 × 103 m / s. If the fuel budgeted for this action is 400 kg, which of the following is velocity of the exhaust gas required if the ship mass is 7.38 × 103 kg?
-5.5 × 104 [m / s]
A stunt man is sliding down the side of a mountain when he manages to catch a tree with a wristwatch winch, which supplies a constant tension, T. Neglecting air friction, if the mountain slope is inclined at an angle θ, what is the acceleration of the stuntman?
-T / m + g sin θ
An empty freight train car of mass 10,000 kg is rolling along a level section of track at 2.00 m / s. It collides with a loaded car of weight 1.96 × 105 N, which is at rest. The cars couple upon collision. Which of the following is the speed of the train after the collision?
0.667 m / s
Tricia's giant jack-in-the-box, Jerry, has now come to life, and wants revenge on her. While Tricia is away, Jerry devises a hydraulic press under Tricia's bed. The press allows Jerry to apply 20 times the force on Tricia's bed that he applies to the piston on his side. What is the ratio of the area of the piston on Jerry's side to the area of the piston under the bed?
1/20
A new high-speed plane is flying horizontally at a speed of 0.75 c (this is not at all realistic). In the reference frame of the ground, the plane flies 1260 m above the ground. How high off the ground does the plane fly in its own reference frame?
1260 m
A 1,450 kg car moves with a speed of 25.0 m / s when it collides with a stationary car having a mass of 1,550 kg. The two vehicles lock bumpers on impact. The two cars then collide with a stationary third car of mass 1,250 kg. During this second impact, the third vehicle becomes attached to the second but the first car is breaks free and moves at 0.125 m / s in the opposite direction. Which of the following is the final velocity of the second and third cars after the final collision?
13.01 m / s
How fast must a baseball move as it leaves your hand if it reaches a maximum height of 15.0 m above the point where it left your hand?
17.1 m / s
When an asteriod that is headed directly for Earth is a distance of 8 Earth radii from Earth's center, it has a speed of 15 km / s. What is the speed of the asteroid when it collides with the Earth? Ignore any frictional effects of the atmosphere. The mass of the Earth is 5.98 × 1024 kg and the Earth's radius is 6.37 × 106 m.
18.3 km / s
Consider a sphere with a radius of 4.0830 m. What is its volume?
285.12 m 3
How many significant figures are in the quantity 9.86 m/s 2?
3
A pendulum bob has mass of 0.750 kg and is on a pendulum arm of length 1.00 m. The pendulum is pulled back so that the arm makes an angle of 60.0° from the vertical and is then released. Which of the following is the speed of the mass when it reaches its lowest point?
3.13 m/s
A projectile is launched from a height of 250 m with initial horizontal velocity of 50 m/s. What is the horizontal range of the projectile?
357 m
An amusement park game consists of throwing a quarter into a small bowl. If you win, you get to take home a giant purple stuffed elephant. The dish is on a shelf that is 0.4 m above the point where the quarter leaves your hand. The horizontal distance between the bowl and the place where the quarter leaves your hand is 1.8 m. Ignoring air drag, if you toss the quarter at an angle of 60°, what initial velocity is needed to bring home the giant purple stuffed elephant?
4.8 m / s
Consider a mass of 85kg lying on the ground. The coefficient of static friction between them is us = 0.65. What is the minimum force you need to apply in order to slide the mass?
541 N
You are rollerblading along the strand in Venice Beach, CA. You start at Muscle Beach at a speed of 8 km / hr. After skating 2.3 km you hit a pebble and a wheel falls off your skate. Luckily you were going slowly when it happened so you don't fall down. You take off your skates and walk 10 minutes to the rollerblade repair shop on the strand, which is 0.8 km away. Assuming the strand is perfectly straight, what is your average velocity?
6.7 km / hr
Cats have amazing control over their bodies. If you hold a cat upside down a moderate height off the floor and drop it, it manages to right itself in midair and land on its feet. Isn't this a violation of the conservation of angular momentum? After all, the cat starts upside down, and then it somehow rotates until it is right-side up. Which of the following is the most plausible explanation for this phenomenon?
By manipulating its body, a cat can control the moment of inertia of different parts of its body in such a way that it can reorient itself in midair despite the fact that its angular momentum is zero the whole time.
The gravitational force between two objects has a magnitude of F. If both masses were doubled and the distance between them doubled, the new force would have which of the following magnitudes?
F
Car 1 of mass 700 kg is slowly moving along at 0.500 m / s when it is hit from behind by car 2 speeding along at 15.0 m / s. After collision, car 1 has a new speed of 8.00 m / s in the same direction. Which of the following is the force with which car 2 must have struck car 1, if the collision lasted for 0.932 s? Also, knowing that conservation of momentum applies to the situation, what is car 2's speed after the collision (v2 f ) if it has a mass of 850 kg?
F = 5.63 × 103 N v2 f = 8.82 m / s
Imagine that you push down on an object that is sitting on a frictionless table. Which of the following diagrams includes all the forces acting on the object?
F W down, N up
A 0.500 kg steel ball is dropped from a height of 4.00 m onto a horizontal steel slab. The collision appears elastic in that the ball rebounds to its original height. If the collision lasts for 2.00 × 10−3 s, which of the following is the impulse imparted to the ball and the average force applied to the ball during the collision?
I = 8.85 kg•m / s F = 4.43 × 103 N
How can you calculate the magnitude of a vector using scalar products?
Multiply it by itself and take the square root.
Which of the following statements concerning friction is incorrect?
The force of static friction ( fs ) between parallel surfaces in contact is given by: fs = μsN.
If two objects with the same radius, one with I1 = I and the other with I2 = 2I, both roll down an incline, which would reach the ground first?
The object with I1 = I.
Which of the following statements concerning an object in free fall through the atmosphere is incorrect?
The speed of a falling object increases due to the frictional force of air drag.
Which is not a reason why measurements are important?
They give us an absolute analysis of the world around us.
When designing elevators, it is important to consider the maximum tension a cable will support. Which of the following causes a maximum tension?
accelerating upward
Which of the following objects has the greatest kinetic energy?
an object of mass 2m and speed 3v
Which of the following is involved in uniform circular motion?
constant angular velocity
Which of the following correctly shows the location of the center of mass of this system?
d - near bottom
In Newtonian physics, kinetic energy equals ½ mv 2. Which of the following is the relativistic definition of kinetic energy?
d) m0c2 - m0c2
A vector is quantity that requires both magnitude and ________.
direction
Consider two objects sliding down an incline without rolling. If the objects don't have the same mass, the heavier object will accelerate at a faster rate than the lighter one.
false
Evaluate the following statement as true or false. Kepler's first law of planetary motion states that the Sun is at the center of a planet's elliptical orbit.
false
A force is applied to an object as shown. What is the direction of the torque vector?
into the screen
Which of the following is not an example of a vector?
mass
The integral (squiggle)dt is called the angular impulse. It is equal to
the change in angular momentum
A truck weighing 1000 N moves at 5.89 m / s when it has an elastic collision with another vehicle. The second vehicle, weighing 981 N, was stationary but free to move. Which of the following is the final velocity of the first vehicle after the collision?
v1 f = 0.0565 m / s
A truck that weighs 1000 N moves at 5.89 m / s when it hits another vehicle in an elastic collision. The second vehicle, weighing 981 N, was stationary but free to move. Find the final velocity of the second vehicle after the collision.
v2 f = 5.95 m / s
A certain galaxy is receding from observers on Earth at a speed of 0.94 c. Within that galaxy, a star explodes, sending hot gases back towards the Earth. Relative to the galaxy, these gases travel at a speed of 0.67 c. What is the speed of the gases relative to Earth?
0.73 c
A squirrel knocks an acorn loose near the top of a tree. If an observer on the ground were sitting 4 m directly below the acorn, how much time does the observer have to move out of the way before getting hit on the head?
0.9 s
In the relativistic case, which of the following is equal to the kinetic energy when an object is at rest?
0
What is the acceleration of a skydiver at terminal velocity whose mass is 80 kg and cross-sectional area is 14 m2. The density of the air he is falling through is 0.9984 g / m3. The drag coefficient has a value of 0.485.
0
A 17 kg particle... magnitude equal to
0.00 Nm
The motor of a toy train quits when the train reaches the top of the far left hill in the diagram. When the train of mass of 7.62 kg gets to the top of this hill, it is moving at a speed of 0.100 m/s. When the train finally makes it up the last hill, it uses all of its available mechanical energy to compress the spring. Which of the following is the distance the spring compresses if the spring constant is 1.00 × 105 N/m.
0.0119 m
In a particle accelerator, two particles collide head-on with each other. Their total masses are 1.67 × 10−27 kg and 9.1 × 10−31 kg. If the less massive one experiences an acceleration of 45 m / s2, what is the acceleration of the other particle?
0.025 m / s2
A juggler is juggling 3 balls. If she throws them 2.4 m in the air at an angle of 80° relative to the horizontal, what is the time between throws? (You should ignore air drag and the time it takes for the juggler to move balls from one hand to the other.)
0.47s
The conversion factor between inches and centimeters is: 1 in. = 2.540 cm. How many meters are in 4.00 feet?
1.22 m
If y = 0 is chosen to be at the ground level, which of the following is the gravitational potential energy of a 500 lb weight that was lifted 3 ft from ground level?
1.50x103 ft-lb
Which of following is the resultant gravitational force acting on the 100 kg mass in the diagram?
1.56
Laura is listening to a record spinning at 45 rpm (revolutions per minute). When she switches the speed selector on the record player to 33 rpm, it takes 2.7 seconds for the record player to change to the new speed. How many revolutions does the record make during this time? Assume that the angular acceleration of the record is constant.
1.8
A roller coaster has 8 cars, each of mass of 95.0 kg. The first hill of the ride is 24.8 m above the ground. Which of the following is the gravitational potential energy of the train once the last car had reached the top of the hill?
1.85x105 J
Recently it was discovered that a planet with mass 1.3 × 1028 kg orbits the star 70 Virginis, which is 59 light years from the Earth. 70 Virginis has approximately the same mass as the Sun, at 1.9 × 1030 kg. If the planet is in a nearly circular orbit of radius 7.1 × 1010 m what is the period of the planet in terms of Earth-days?
122 days
A small airplane and a hot air balloon are moving horizontally towards each other. Relative to the ground, the plane travels at a speed of 135 m / s and the balloon travels at a speed of 7 m / s. Suppose that someone throws a tomato out of the basket of the hot air balloon, as shown. At a particular instant, the tomato is traveling horizontally with a speed of 28 m / s relative to the balloon. According to Galilean (or classical) relativity, what is the velocity of the tomato relative to the airplane?
170 m/s
A cart with mass m1 = 24 kg lies on an incline that makes an angle of 17° with the horizontal. The coefficients of static and kinetic friction are 0.7 and 0.5 respectively. The cart is tied by an ideal rope that runs through a frictionless pulley as shown in the diagram. What tension do you need to apply to the free end of the rope in order to make the cart go up the incline at a constant velocity?
181
A tire is inflated to a gauge pressure of 2.0 atm. As the car is driven the temperature of the tire increases from 20oC to 45oC, and simultaneously the volume of the tire increases by 5%. What is the gauge pressure of the tire at the higher temperature?
2.1 atm
Ollie Oksenfrei.... What are the magnitude and direction of her acceleration at t = 3s?
2.12m/s and 81.87 degrees
A large top... velocity of the top?
3.0 rad/s
Three pool balls of equal mass are resting on a horizontal frictionless surface. The cue ball (Ball 1) of mass 700 g is rolled into a stationary pool ball (Ball 2) and rebounds at 1.00 m / s in the direction from which it came. Ball 2 does not move, but it is touching another pool ball (Ball 3), which rolls away at 4.00 m / s. Which of the following is the initial speed of the cue ball, v1i? Also, given that the encounter between the cue ball and cue stick lasts for only 0.0500 s, which of the following is the average force delivered F to the cue ball by the stick?
3.00 and 42.0 N
A tire is filled at a gas station to the recommended pressure of 35 psi. Which of the following statements is most probable?
3.4 x 10^5 Pa
A projectile is launched at 20 m / s at a 60° angle from the horizontal. How much time does it take for the projectile to land, assuming it lands on ground that is level with the launch site?
3.6
A scientific team has designed a thin film that enables them to measure normal forces from surfaces. They lay this thin film on a flat surface, and on top of it they place a vase. The normal force of the table on the vase is 35 N. What do you expect the vase's mass to be?
3.6 kg
Two particles collide and come off at right angles, as shown. In the frame of the laboratory, both particles move at 0.85 c. Suppose that at this instant in the unprimed frame, each of the particles is 2.0 m from the point of collision. What is the distance between the particles in the frame of the horizontally moving particle?
4.3 m
At the end of a roller coaster ride the track flattens out and the brakes are applied to the cart. At the moment the brakes are applied, the cart is going 85 km / h. Assuming that the acceleration is constant and that the flat part of the track is 60 m long, how long does it take the cart to come to a halt?
5.1 s
A 3000 kg satellite is in a circular orbit around the Earth. The radius of the orbit is r0. Using the energy diagram, what is the value of r0? The mass of the Earth is 6 × 1024 kg.
6.0 x 10^7 m
At any given instant in the rotational motion of a windmill, one of its blades is closest to pointing straight up (at certain instants, there are two blades that are equally close). Call that blade the "superior" blade at that instant. Starting from rest with one of its five blades pointing straight up, a windmill is angularly accelerated at a constant rate of 4.38 rad / s2. At what angle is the superior blade from vertical exactly 35 seconds later?
6.1 rad
A surveillance plane weighing 1.91 × 104 N is flying horizontally at a velocity of 59.4 m / s due west in thick clouds. Suddenly the plane is struck a glancing blow from another plane. Before impact, this smaller plane weighing 9.74 × 103 N was traveling at 114 m / s due northwest at constant altitude. Immediately after impact, the second plane is knocked of course to a heading of 89.8 m / s at 35.2° north of west. Which of the following is the velocity of the surveillance plane after the collision?
64.8 m / s at 13.1° north of west
In a traffic accident, two motorcycles, A and B, collide with each other. Their total masses are 180 kg and 134 kg. If the more massive one experiences an acceleration of 50 m / s2, what is the acceleration of the other motorcycle?
67 m / s2
Exhaust gas from a rocket ship is released at a speed of 1,000 m / s so that the craft accelerates from 100 m / s to 200 m / s. How much fuel is necessary to complete this acceleration if the mass of the ship was originally 10,000 kg?
951.6 kg
A wheel experiences a positive constant angular acceleration. Which of the following best describes the graph of the angular position of the wheel as a function of time?
It is a parabola that opens upwards.
Clockwise rotations are always positive.
false
Which of the following is not a unit of the metric system or Système International?
yard
John Wilkins hits a baseball with an initial velocity of 110 mph at an angle of 35° from the horizontal. The backfield fence is 403 ft from home plate. Did "The Big J" hit a home run?
yes
This diagram illustrates a water molecule (H2O). The oxygen atom has a mass of roughly 16 units, and the hydrogen atoms each have a mass of roughly 1 unit. The distance between the oxygen and hydrogen nuclei is 0.96 angstroms (an angstrom, denoted Å, is equal to 10−10 m). If the oxygen atom is located at y = 0, where is the vertical position of the center of mass of the molecule? Assume that hydrogen atoms lie towards positive y.
0.063 Å
In a game of marbles, a 60 g marble is rolling at 8.00 cm / s when it collides with a stationary marble. the 60 g marble takes off at a 27° angle at a reduced speed of 4.89 cm / s. The second marble moves at a rate of 3.21 cm / s at a 31.7° angle. Which of the following is the mass of the second marble?
0.0800 kg
A car travels with a speed of 3.5 m / s, and then accelerates to 5.5 m / s in 4 s. Which of the following is the average acceleration of the car?
0.5 m / s2
If the cross product of a vector of length 5 and a vector of length 3 results in a vector of length 10, what is the angle between them?
42°
Which of the following is not a unit of work?
J⋅m
Which of the following is not a vector quantity?
power
A 200 g plastic ball is at rest on a frictionless incline 0.658 m above the surface of a table. The ball then rolls down the incline and across the table, coming to rest after a distance of 2.45 m. Which of the following the average friction on the ball while rolling across the table.
0.527 N
Two rocket ships are flying in opposite directions at high speeds over the Earth's surface. Relative to the ground, one travels at 0.63 c, while the other travels at 0.91 c. How fast does one ship move relative to the other?
0.98 c
Which of the following is a form of Hooke's law, where Fs is a spring force?
Fs = -kx
Calculate x=vt+1/2at2, where v = 0.227 m/s. t = 11.1s, and a = 9.80 m/s2.
606 m
A motorcycle is moving with a speed of 8.3 m / s when it begins to brake and slow down at a constant rate. If the acceleration is 3.1 m / s2, how much further will the motorcycle travel before it comes to a complete stop?
11 m
A mass m is dropped from rest to the ground from a height h. Which of the following is correct?
When it strikes the ground the speed of the mass is independent of m.
Which of the following is the gravitational force between the Earth and the Moon? The Earth's mass is 6x10 24 kg, the moon's mass is 7.4 x 10 22 kg, and the distance between the centers of mass is 3.8 x 10 8 m.
2.1 x 10 20 N
A freight train is traveling at a speed so that the angular velocity of its wheels is 38 rad / s. The engineer decides to accelerate the train to a speed 1.5 times faster than before. If the acceleration of the train corresponds to an angular acceleration of 0.80 rad / s2, how long does it take for the train to reach its new speed?
24 s
Tom and Joe are trying to fly a new style of kite that they have invented. Both of them are holding strings attached to the kite. The tension in each string is 126 N. The angle between the strings is 36°. Unfortunately, the kite will not rise in the air, and the strings held by Tom and Joe are essentially parallel to the ground. Tom and Joe have run a distance of 100 m trying to get the kite to fly. How much work have they done on the kite?
24,000 N • m
King Kong is holding a woman on top of a skyscraper when she suddenly slips out of his hand. How tall is the building if Superman has a minimum time of 2.30 s to catch the woman before she hits the ground?
25.9 m
A car is decelerating from 60 mph to 0 mph in 122 ft. If the tires have a diameter of 18 in., how many revolutions do the wheels make during the deceleration?
25.9 revolutions
A train is on an incline and has a mass of 2.36 × 103 kg. It initially coasts at 27.8 m/s. Which of the following is the speed of the train at position B. Assume no additional assistance from the engine.
34.2 m/s
When viewed from above, a particular var has an area A1. Each of its four tires holds a pressure Pr and contacts the ground with an area of A2. If atmospheric pressure is Patm, which of the following is the correct expression for the weight of the car?
4PrA2
You are going for a bike ride. You ride down a straight road at a speed of 9.0 mi / hr. Just as you pass the point which is 3.6 miles from your starting point, you develop a flat tire. You get off you bike and walk it to a bike shop 0.5 mile further down the road. The walk to the bike shop takes 12 minutes. What was your average velocity for the entire trip?
6.8 mi / hr
Suppose a parachutist with a mass of 67 kg jumps from an airplane. A few seconds after the person opens the parachute she measures her velocity—she is falling down at constant speed of 15 m / s. What is the force of air drag on her parachute?
656.6 N
NASA wants to launch a new satellite that will remain in a circular orbit 300 km above the surface of the Earth. Determine the orbital speed necessary for the satellite to remain in this orbit if the mass of the Earth is 5.97 × 1024 kg and its radius is 6.38 × 106 meters.
7720 m / s
Kylie throws Kyra a kiwi. The kiwi leaves Kylie's hand at a height of 1.3 m from the ground and Kyra grabs it out of the air at a height of 1.6 m. Kylie throws the kiwi at an angle of 33° relative to the horizontal. The kiwi is in the air for 1.1 s. How far apart are Kylie and Kyra standing? (Assume there is no drag force that no wind is blowing.)
9.6 m
Consider a spring that is stretched from its equilibrium position x0, where x0 = 0, to a position x, where x is positive. Which of the following describes why the work done by a spring is negative?
All of the choices are correct.
A dolphin trailing one of the Navy's aircraft carriers decides swim underneath the carrier. Does the presence of the ship affect the pressure changes the dolphin feels as it dives?
No, the pressure remains the same as when the ship wasn't there.
An observer O notes a particle moving to the right with velocity v. Another observer O ′ is moving with speed v relative to O along the direction of the motion of the particle. Which of the following is the value of the particle's mass as measured by O and O ′?
O measures m and O' measures m0
Which of the following statements concerning friction between the surfaces of two objects is correct?
The force of friction mostly depends on the nature of the two surfaces.
Scientists are planning to put Ruffs the dog on the first spaceship capable of traveling at speeds near the speed of light. In the interest of saving space, the ship designers have made the cabin of the ship very small, so that Ruffs can barely fit inside. The dog will still be comfortable, they reason, because he will be Lorentz contracted during the trip. What is the best response to this reasoning?
The reasoning is not sound, because Ruffs will be Lorentz contracted relative to the Earth, but not relative to the ship
As shown, a crate of oranges and a crate of apples, each with a different mass, are attached by a rope (with tension Toa). A second rope (To ) is attached to the crate of oranges, and the entire system is pulled with a constant acceleration a by this rope. Which of the following is true of the tensions?
Toa > To
Two inertial observers are moving with relative speed v. An observer, O, measures the speed of an object in her reference frame to be u and notes O's speed to be v. What is the speed of the object in the prime inertial frame according to O ?
u = u-v/1-uv/c2
The position of an object along the x-axis is described by the formula x = 3t 2 − 2t. Which of the following are the correct formulas for the velocity and acceleration of the object?
v = 6t − 2, a = 6
A 309 g glass rolls down an incline and onto a horizontal platform where it hits a beverage can that is laying at rest on its side. The top of the incline is 11.0 cm above the horizontal platform. The beverage can is initially at rest and weighs 7.35 N. Which of following is the final velocity of the glass?
−0.612 m / s
Two children are playing catch in a passenger train. An observer on the ground measures that the train is traveling at 70 mph. As the train passes the observer, he measures that the ball is thrown with half of the speed as the passenger train. What velocity do the children measure for the ball? (Assume the positive direction is the direction in which the train is moving.)
−35 mph