Physics 1 Final Exam
An object is moving with constant non-zero velocity. Which of the following statements about it must be true?
The net force on the object is zero
When a car goes around a banked circular curve at the proper speed speed for the banking angle, what force cause it to follow the circular path?
The normal force of the road
Jill does twice as much work as Jack does and in half the time. Jill's power output is
4 times Jack's power output
A 1200 kg car moving at 13.4m/s suddenly collides with a stationary car of mass 1500kg. If the two vehicles lock together, what is their combined velocity immediately after the collision?
5.9 m/s
When is the angular momentum of a system constant?
Only when no net external torque acts on the system.
The figure shows a graph of the position x of two cars, C and D, as a function of time T. According to this graph, which statements about these cars must be true?
- both have same acceleration - cars meet at time t=10s.
The sum of two vectors of fixed magnitudes has the greatest magnitude when the angle between these two vectors is
0
Write out the tuber 8.42*10^-5 in full with a decimal point and correct # of 0s.
0.0000842
A 45 kg person steps on a scale in an elevator. The scale reads 460N. What is the magnitude of the acceleration of the elevator?
0.422m/s2
Calculate the average force a bumper would have to exert to bring a 1200kg car to rest in 15 cm when the car had the initial speed of 2.0m/s (about 4.5 mph)
1.6x10^4
Suppose our sun had 4 times its present mass but the earth orbited it at the same distance as it presently does. What would be the length of the year on the earth under those conditions?
1/2 as long as the present year
Two satellites A and B of the same mass are going around Earth in concentric orbits. The distance of satellite B from Earth's center is twice that of satellite A. What is the ratio of the centripetal force acting on B compared to that acting on A?
1/4
Two blocks, A and B, are being pulled to the right along a horizontal surface by a horizontal 100-N pull, as shown in the figure. Both of them are moving together at a constant velocity of 2.0 m/s to the right, and both weigh the same. Which of the figures below shows a correct free-body diagram of the horizontal forces acting on the lower block, B?
100N on both sides of box B
A cart starts from rest and accelerates uniformly at 4.0 m/s^2 for 5.0 sec. It next maintains the velocity it has reached for 10 sec. Then it slows down at a steady rate of 2.0 m/s^2 for 4.0 sec. What is the final speed of the car?
12 m/s
A force produces power P by doing work W in a time T. What power will be produced by a force that does six times as much work in half as much time?
12P
An object that weighs 75N is pulled on a horizontal surface by a horizontal pull of 50 N to the right. The friction force on this object is 30N to the left. What is the acceleration of the object?
2.6 m/s2
an object that weighs 75N is pulled on a horizontal surface by a pull of 50N to the right. The frictional force on the object is 30N to the left. What is the acceleration?
2.6 m/s2
An aluminum cylinder weight 50N in air and 30N when the cylinder is submerged in water. What is the weight of the water displaced by the cylinder?
20N
If you want to double the momentum of a gas molecule, by what factor must you increase its kinetic energy?
4
In addition to 1m=39.37 in, the following exact conversion equivalents are given: 1 mile=5280 ft, 1 ft=12 in, 1 hr=60 min, 1 min= 60 sec. If a particle has a velocity of 9 miles per hour, its velocity, in m/s, is closest to
4.0 m/s
Two vectors, of magnitudes 20 mm and 50 mm, are added together. Which one of the following is a possible value for the magnitude of the resultant?
40 mm
An aero plane is traveling 800 km/hr in a direction 30 degrees north of east. Calculate the component of the velocity along east direction and along north direction. How Far East will the plane be after 1 hr?
400 km/hr (?)
Two planets have the same surface gravity, but planet B has twice the radius of planet A. If planet A has mass m, what is the mass of planet B?
4m
What is the sum of 1.49 + 3.212 + 1.9 written with the correct number of significant figures?
6.6
A certain CD-ROM disk can store approximately 6.0x10^2 megabytes of information where 10^6 bytes=1 megabyte. If an average word requires 9.0 bytes of storage, how many words can be stored on one disk?
6.7x10^7
How much work would a child do while pulling a 12-kg wagon a distance of 3.0 m with a 22 N force?
66 J
What is the sum of 1.53+2.786+3.3 with the correct sig fig?
7.6
What is the mass of an object that experiences a gravitational force of 791N near earth's surface where g=9.80 m/s2?
80.7 kg
What is the angular speed, in rad/s, of a flywheel turning at 813.0rpm?
85.14 rad/s
A motorist travels for 3.0h at 80 km/h and 2.0h at 100 km/hr. What is average speed for trip?
88 km/h
A block of mass m sits at rest on a rough inclined ramp that makes an angle with the horizontal. What must be true about normal force on the block due to the ramp?
F=mg cos angle
The graphs shown show the magnitude F of the force exerted by a spring as a function of the distance x the spring has been stretched. For which one of the graphs does the spring obey Hooke's law?
Graph B (steadily increases upward)
Two men, Joel and Jerry, push against a car that has stalled, trying unsuccessfully to get it moving. Jerry stops after 10 min, while Joel is able to push for 5.0 min longer. Compare the work they do on the car.
Neither of them does any work
If the units of your answer are kg•m2/s3, which of the following types of quantities could your answer be? (There could be more than one correct choice.)
Power
A satellite of mass M takes time T to orbit a planet. If the satellite had twice as much mass, the time for it orbit the planet would be
T
Suppose that a car traveling to the west begins to slow down as it approaches a traffic light. Which of the following statements about its acceleration is correct?
The acceleration is towards the east
Two cyclists who weigh the same and have identical bicycles ride up the same mountain, both starting at the same time. Joe rides straight up the mountain, and Bob rides up the longer road that has a lower grade. Joe gets to the top before Bob. Ignoring friction and wind resistance, which one of the following statements is true?
The amount of work done by Joe is equal to work done by bob, but average power exerted by Joe is greater
As a rock sinks deeper and deeper into water of constant density, what happens to the buoyant force on it?
The buoyant forces first increase and then remain constant
Suppose that an object travels from one point in space to another. Make a comparison between the displacement and the distance traveled.
The displacement is either less than or equal to the distance traveled
Which one of the following is an accurate statement?
The ratio of tensile stress to tensile strain is called Young's modulus
If you pound a feather with a hammer, which one feels a greater force?
The size of force is exactly the same on both of them
The motions of a car and a truck along a straight road are represented by the velocity-time graphs in the figure. The two vehicles are initially alongside each other at time t = 0. At time T, what is true of the distances traveled by the vehicles since time t = 0?
The truck will have traveled further than the car
When a rigid object rotates about a fixed axis, what is true about all the points in the object?
They all have same angular speed and acceleration
Consider a deer that runs from point A to point B. The distance the deer runs can be greater than the magnitude of its displacement, but the magnitude of the displacement can never be greater than the distance it runs.
True
The graph in the figure shows the tensile stress as a function of the tensile strain in a certain wire. What does the slope of this graph give us for this wire?
Young's modulus for the material of the wire
The slope of a velocity vs time graph gives
acceleration
If the position versus time graph of an object is a horizontal line, the object is
at rest
A lightweight object and a very heavy object are sliding with equal speeds along a level frictionless surface. They both slide up the same frictionless hill with no resistance. Which object rises to greater height
both slide to same height
Consider 2 vectors A and B shown in figure. The difference A-B is illustrated by
choice C (to left and up at angle)
A horse pulls a cart with force F. As a result of this force the cart accelerates with constant acceleration. The magnitude of the force that the cart exerts on the horse
equal to the magnitude of F
A bucket is being lowered by a very light rope with a constant downward velocity. The tension on the rope must be
equal to the weight of the bucket
If you swing a bucket of water fast enough in a vertical circle, at the highest point the water does not spill out. This happens because an outward force balances the pull of gravity on the water.
false
When adding 2 numbers, the number of sig figs in the sum is equal to the number of sig figs in the least accurate of the numbers added
false
If a tree is 15 m tall, its height expressed in feet is x ft, where x is
greater than 15
The reason an astronaut in an earth satellite feels weightless is that
he's falling
A person sits on a freely spinning lab stool that has no friction in its axle. When they extended their arms
her moment of inertia increases and her angular speed decreases
For general projectile motion with no air resistance, the horizontal component of a projectile's acceleration
is always zero
When an object moves in uniform circular motion, the direction of its acceleration is
is directed toward the center of its circular path
A horse pulls a cart with force F. As a result of this force, the cart accelerates with constant acceleration. The magnitude of the force that the cart exerts on the horse
is equal to the magnitude of F
An object moving in the +x direction experiences an acceleration of +2.0m/s2. This means the object
is increasing its velocity by 2.0 m/s every second
Halley's Comet is in a highly elliptical orbit around the sun. Therefore the orbital speed of Halley's Comet, while traveling around the sun,
it increases as it nears the sun
Suppose that a car traveling to the west begins to slow down as it approaches a traffic light. Which of the following statements about its acceleration is correct?
its acceleration is positive
If a woman weighs 125 lb, her mass expressed in kg is
less than 125
If the velocity versus time graph of an object is a horizontal line, the object is
moving with zero acceleration
a wooden block contains some nails so that its density is exactly equal to that of the water. If it is placed in a tank of water and released from rest when completely submerged it will
remain where it is released
For general projectile motion with no air resistance, the horizontal component of a projectile's velocity
remains a non zero constant
For general projectile motion, the horizontal component of a projectile's velocity
remains a non zero constant
Ball A is dropped from the top of a building. One second later, ball B is dropped from the same building. As time progresses, the distance between them
remains constant
Satellite A has twice the mass of satellite B, and moves at the same orbital distance from Earth as satellite B. Compare the speeds of the two satellites.
speed of B is equal to speed of A
A stone can slide down one of four different frictionless ramps, as shown in figure. Which ramp with the speed of ball be greatest?
speed of ball is the same for all ramps
When you throw a pebble straight up with initial speed V, it reaches a maximum height H with no air resistance. At what speed should you throw it up vertically so it will go twice as high?
square root of 2 V
A car is moving with a speed of 32.0 m/s. The driver sees an accident ahead and slams on the brakes, causing the car to slow down with a uniform acceleration of magnitude 3.50 m/s^2. How far does the car travel after the driver put on the brakes until it coms to a stop?
t=9.14 sec.
The current definition of the standard meter of length is based on
the distance traveled by light in a vacuum
Two equal-magnitude forces are applied to a door at the doorknob. The first force is applied perpendicular to the door, and the second force is applied at 30° to the plane of the door. Which force exerts the greater torque about the door hinge?
the first force
The current definition of the standard second of time is based on
the frequency of radiation emitted by cesium atoms
When a car goes around a circular curve on a horizontal road at constant speed, what force causes it to follow the circular path?
the friction force from the road
When you ride a bicycle, in what direction is the angular velocity of the wheels?
to your left
If an object remains at rest, then the sum of both the external torques and the external forces on the object must be zero.
true
Swimmers at a water park have a choice of two frictionless water slides, as shown in the figure. Although both slides drop over the same height h, slide 1 is straight while slide 2 is curved, dropping quickly at first and then leveling out. How does the speed v1 of a swimmer reaching the bottom of slide 1 compare with v2, the speed of a swimmer reaching the end of slide 2?
v1=v2
When throwing a ball straight up, which of the following is true about its velocity v and its acceleration a at the highest point in its path?
v=0 but a doesn't equal 0
The graphs shown show the magnitude F of the force exerted by a spring has been stretched. For which one of the graphs does the spring obey Hooke's law?
B. Steadily moves upward
A racing car accelerates uniformly from rest along a straight track. This track has markers spaced at equal distances along it from the start, as shown in the figure. The car reaches a speed of 140 km/h as it passes marker 2.
Before marker 1
Three cars (car L, car M, and car N) are moving with the same speed and slam on their brakes. The most massive car is car L, and the least massive is car N. If the tires of all three cars have identical coefficients of kinetic friction with the road surface, for which car is the amount of work done by friction in stopping it the greatest?
Car L
A fireman is sliding down a fire pole. As he speeds up, he tightens his grip on the pole, increasing the vertical frictional force that the pole exerts on the fireman. When the force on his hands equals his weight, what happens to fireman?
Continues to descend but with constant speed
A driver traveling 18m/s when she sees a redlight ahead. the car is capable of reaccelerating at the rate of 3.55 m/s2 when she applies the brake. How far does the car travel after the brake is applied? (kinematic equation)
x-x0=45.6m
A 0.14 kg baseball is dropped from rest from a height of 2.0m above the ground. What is the magnitude of its momentum just before it hits the ground if we neglect air resistance?
0.88 kg*m/s
A runner runs around a track consisting of 2 parallel lines 96m long connected at ends by 2 semicircles with radius of 49m. She completes one lap in 100 seconds. What is average velocity?
0m/s
If Earth had twice its present mass but it orbited at the same distance from the sun as it does now, its orbital period would be
1 year
If a net force accelerates a 4.5kg tool at 40m/s2, what acceleration would have the same next force give to an 18 kg tool?
10 m/s2
A stone thrown upward with velocity of 8m/s. Neglecting air resistance, what is the velocity of the sone after 0.5 sec?
3.1 m/s
The wavelength of a certain laser is 0.35 micrometers, where 1micrometer=1x10^-6m. Express this wavelength is nanometers
3.5x10^2
A 65 kg woman is standing on a scale inside an elevator. If the elevator is accelerating downward at 3.2 m/s2, what is the reading on the scale? (F=mg-N)
425 N
A stunt driver running 80 mph dives from the edge of a 100m high vertical cliff. The mass of the car and driver is 1550kg. What would be the speed of the car when it hit the ground? (Use conversion of energy)
44 m/s
Which one has larger kinetic energy: a 500-kg object moving at 40 m/s or a 1000-kg object moving at 20 m/s?
500 kg object
What is 56+(32.00)/(1.2465+3.45) written with the correct number of significant figures?
63
A net force of 200N acts on a 100 kg boulder, and a force of the same magnitude acts on a 130g pebble. How does the rate of change of the boulder's momentum compare to the rate of change of the pebble's momentum?
Equal to
Two small balls, A and B, attract each other gravitationally with a force of magnitude F. If we now double both masses and the separation of the balls, what will now be the magnitude of the attractive force on each one?
F
Two small objects, with masses m and M, are originally a distance r apart, and the magnitude of the gravitational force on each one is F. The masses are changed to 2m and 2M, and the distance is changed to 4r. What is the magnitude of the new gravitational force?
F/4
In a collision between a huge SUV and a small car, the SUV exerts a larger force on the hybrid than the hybrid exerts on the SUV
False
Two spheres have the same radius and equal masses. One is made of solid aluminum, and the other is made from a hollow shell of gold. Which one has the bigger moment of inertia about an axis through its center?
Hollow gold
A ball is thrown straight up, reaches a max height, then falls to its initial height. Which of the following statements about the direction of the velocity and acceleration fo the ball as its going up is correct?
Its velocity points upward and acceleration is downward
Two cars go around a banked curve at the proper speed for the banking angle. One car has tires with excellent traction, while the other car has bald slippery tires. Which of these cars is more likely to slide on the pavement as it goes around the curve?
Neither car will slide
A girl attaches a rock to a string, which she then swings counter-clockwise in a horizontal circle. The string breaks at point P in the figure, which shows a bird's eye view. Which path will the rock follow?
Path B (straight from the release point)
A 10kg rock and a 20kg rock are dropped from the same height and experience no significant air resistance. If it takes the 20 kg rock a time T to reach the ground, what time will it take the 10 kg rock to reach the ground?
T
A push of magnitude P acts on a box of weight W as shown in the figure. The push is directed at an angle θ below the horizontal, and the box remains a rest. The box rests on a horizontal surface that has some friction with the box. The normal force on the box due to the floor is equal to
W+P sin angle
In an air free chamber, a pebble is thrown horizontally, and at the same instant a second pebble is dropped from the same height. What time do these pebbles hit the ground
at the same time
An auto manufacturer advertises that their car can go "from zero to sixty in eight seconds." This is a description of what characteristic of the car's motion?
average acceleration
Suppose a ball is thrown straight up and experiences no air resistance. What is its acceleration just before it reaches its highest point?
exactly g
A boat loaded with rocks is floating in pool. If rocks are thrown into pool the water level of pool after rocks reach bottom
falls
If the rockets of a spaceship in outer space (far from all gravity) suddenly lose power and go off, the spaceship will gradually slow to a stop.
false
If the sum of the external forces on an object is zero, then the sum of the external torques on it must also be zero.
false
When determining the number of significant figures in a number, zeroes to the left of the decimal point are never counted
false
scientists use the metric system chiefly because it is more accurate than the English system (T/F)
false
A hypothetical planet has a mass of 1/2 earth and a radius of 2x earth. What is acceleration due to gravity on the planet in terms of g, the acceleration due to gravity at the surface of the earth?
g/8
Which of the following quantities are units of impulse? (There could be more than one correct answer)
kg*m/s N*s
a hollow sphere of negligible mass and radius R is filled with liquid s that density is p. You now enlarge sphere so its radius is 2R and completely fill it with same liquid. What is density of enlarged sphere?
p
If A+B=C and their magnitudes are given by A+B=C, then the vectors A and B are oriented
parallel to each other in the same direction
A car goes around a circular curve on a horizontal road at constant speed. What is the direction of the friction force on the car due to the road?
perpendicular to the curve inward
You are in a train traveling on a horizontal track and notice that a piece of luggage starts to slide directly toward the front of the train. From this observation, you can conclude that this train is
slowing down
the current definition of standard kg of mass is based on
the mass of an object in france
A merry go round spins freely when Diego moves quickly to the center along a radius of the ride. As he does this, it is true to say that
the moment of inertia of system decreases and angular speed increases
If you stood on a planet having a mass four times that of Earth's mass, and a radius two times that of Earth's radius, you would weigh
the same as you do on earth
Three objects are moving along a straight line as shown in the figure. Taking the positive direction to be to the right, what is the total momentum of this system?
-14.0 Kg*m/s
What is (0.300/0.82) to the proper number of significant figures?
0.37
If a net force accelerates a 4.5 kg tool at 40 m/s2, what acceleration would that same net force give to an 18 kg tool?
10 m/s2
A bicycle has wheels that are 60cm in diameter. What is the angular speed of these wheels when it is moving at 4.0 m/s?
13 rad/s
A 1000 kg sports car needs to accelerate from 20m/s to 50m/s on a flat road in 2 seconds. What is the minimum power of the engine? (Use kinematic equation)
750 KW
a 20 ton truck collides with a 1500 lb car. Which of the following statements must be true?
During the collision, the force on the truck is equal to the force on the car
In the figure, what does the spring scale read? The pulleys are ideal and the strings and scale are also massless.
Exactly 1.0N
Two children, Ahmed and Jacques, ride on a merry-go-round. Ahmed is at a greater distance from the axis of rotation than Jacques. Which of the following are true statements? (There could be more than one correct choice.)
Jacques and Ahmed have the same angular speed, and Ahmed has a greater tangential speed than Jacques.
Mike performed 5 J of work in 10 secs. Joe did 3 J of work in 5 secs. Who produced the greater power?
Joe produced more power
A block of mass m rests on the floor of an elevator that is accelerating upward. What is the relationship between the force due to gravity and the normal force on the block?
N> mg
A small car meshes with a large truck in a head-on collision. Which of the following statements concerning the magnitude of the average force during the collision is correct?
The small car and large truck experience the same average force
Given that A+B=C, and that |A|+|B|=|C|, how are vectors A and B oriented with respect to each other
They are parallel and in the same direction
Inside of a train a ball of weight W is hanging by a light wire at rest from the ceiling. The wire makes an angle θ with the ceiling, as shown in the figure. Which one of the following conditions must be true about the tension T in the wire?
Tsin0=W
A 10 kg rock and the 20 kg rock are dropped at the same time and experience no significant air resistance. If the 10kg rock falls with acceleration a, what is the acceleration of the 20 kg rock?
a
Refer to the figure, which shows four vectors M, N, S, and T. a) vector S as expressed in terms of vectors M and N is given by b) vector T as expressed in terms of vectors M and N is given by
a) B. M-N b) A. M+N
The x and y components of a vector n a horizontal plane are 4.00m and 3.00m, respectively. a)what is the magnitude of this vector? b)what angle does this vector make with the positive y axis?
a)5.00m b)53
A ball is thrown straight with some initial speed. When it reaches the top of its flight (at a height h) a second ball is thrown straight up with the same initial speed. Where will the balls cross paths?
above height h/2
A 75 N box rests on a perfectly smooth horizontal surface. The minimum force need to start the box moving is
any horizontal force greater than zero
A pilot drops a package from a plane flying horizontally at a constant speed. Neglecting air resistance, when the package hits the ground the horizontal location of the plane will
be directly over the package
Two displacement vectors have magnitudes of 5.0 m and 7.0 m, respectively. When these two vectors are added, the magnitude of the sum
could be as small as 2.0m or as large as 12.0 m
A boat carrying a large chunk of steel is floating on a lake. The chunk is then thrown overboard and sinks. What happens to the water level in the lake (with respect to the shore)?
drops
In a mercury barometer at atmospheric pressure, the height of the column of mercury in a glass tube is 760mm. If another mercury barometer is used that has a tube of a larger diameter, how high will the column of mercury be in this case?
equal to 760mm
A steel ball sinks in water but floats in a pool of mercury, which is much denser than water. Where is the buoyant force on the ball greater?
floating on the mercury
A railroad car collides with and sticks to an identical railroad car that is initially at rest. After the collision, the kinetic energy of the system
is half as much as before
A solid sphere and a solid cylinder, both uniform and of the same mass and radius, roll without slipping at the same forward speed. It is correct to say that the total kinetic energy of the solid sphere is
less than the total kinetic energy of the cylinder
The position x, in meters, of an object is given by the equation x=a+bt+ct^2, where t represents time in seconds. What are the SI units of A, B, and C?
m, m/s, m/s^2
You are making a circular turn in your car on a horizontal road when you hit a big patch of ice, causing the force of friction between the tires and the road to become zero. While the car is on the ice, it
moves along a straight line path in its original direction
If the distance to the Moon were doubled, then the force of attraction between Earth and the Moon would be:
one quarter
A ping pong ball is shot into a circular tube that is lying flat (horizontal) on a table top. When the ball leaves the track, which path will it follow?
path 2. It continues in its original direction
In the figure, determine the character of the collision. The masses of the blocks, and the velocities before and after, are shown. The collision is
perfectly elastic
A stunt driver running 80 mph dives out horizontally from the edge of a 100m high vertical cliff. How long would the driver be in the air before hitting ground below the cliff? (vertical kinematic equation)
t=4.5 sec.
Two objects, one of mass m and the other of mass 2m, are dropped from the top of a building. If there is no air resistance, when they hit the ground
the heavier one will have twice the kinetic energy of the lighter one
A waiter fills your water glass with ice water, containing many ice cubes, such that the liquid water is perfectly level with the rim of the glass. As the ice melts,
the liquid water level remains flush with the rim of the glass
A rocket explodes into two fragments, one 25 times heavier than the other. The magnitude of the momentum change of the lighter fragment is
the same as the momentum change of the heavier fragment