Physics Quizzes
As compared to Jack, Jill does twice the work in half the time. Jill's power output is
Four times Jack's power output
A simple pendulum, consisting of a mass m and a string of length L, swings upward, making an angle θ with the vertical. The work done by the tension force is
Zero
Work done by STATIC FRICTION is always
Zero
When an object is in translational equilibrium, the net force acting on the object is non-zero
False
An acorn falls from a tree. Compare its kinetic energy K, to its potential energy U
K increases and U decreases
A person carries a mass of 10 kg and walks along the +x-axis for a distance of 100 m with a constant velocity of 2 m/s. What is the work done by this person?
0 J
How many significant figures are there in: 0.0210, 5.060, 7.10 × 10^-4, 1.0 × 10^-5= 2
0.0210= 3 5.060= 4 7.10 × 10^-4= 3 1.0 × 10^-5= 2
A baseball has a diameter of 75 millimeters. Give the diameter in meters and kilometers
0.075 m 0.000075 km
If vector A has components Ax > 0, and Ay > 0, then the angle that this vector makes with the positive x-axis must be in the range
0° to 90°
Rank the following number in order of increasing number of significant figures: 1, 1001, 10.01, 123
1 < 123 < 1001 and 10.01
Rank the following lengths in order of increasing value: 2 millimeters, 10 micrometers, 0.1 kilometers, and 10 centimeters
10 micrometers < 2 millimeters < 10 centimeters < 0.1 kilometers
On a distant, airless planet, an astronaut drops a rock to test the planet's gravitational pull. The astronaut finds that in the first second of falling (from t=0 to t=1s the rock drops a distance of 1m. How far does the rock drop from t=1s to t=2s?
3m
A house sells for 450,000 dollars. Express the price of the house in kilodollars and megadollars
450 kilodollars 0.450 megadollars
A block rests on a rough, horizontal surface. A force will be applied to the block along one of the four indicated directions (A, B, C, D). Rank the directions in order of increasing force required to make the block move. Indicate ties where appropriate
A < B = D < C
An object is moving with constant non-zero velocity in the +x axis. The velocity versus time graph of this object is
A horizontal straight line
An object is moving with constant non-zero acceleration in the +x axis. The position versus time graph of this object is
A parabolic curve
An object is moving with constant non-zero acceleration in the +x axis. The velocity versus time graph of this object is
A straight line making an angle with the time axis
An object is moving with constant non-zero velocity in the +x axis. The position versus time graph of this object is
A straight line making an angle with the time axis
Two stones, one of mass m and the other of mass 2m, are thrown directly upward with the same velocity at the same time from ground level and feel no air resistance. Which statement about these stones is true?
At its highest point, the heavier stone will have twice as much gravitational potential energy as the lighter one because it is twice as heavy
If the position versus time graph of an object is a horizontal line, the object is
At rest
A sailor drops a pair of binoculars from the "crow's nest" at the top of a sailing ship's mast. When the ship is at rest, the binoculars land at the base of the mast. If the ship is moving forward with constant velocity, and air resistance can be ignored, do the binoculars land in front of the mast (toward the front of the ship), at the base of the mast, or behind the mast (toward the rear of the ship)? Explain
At the base of the mast. The binoculars continue to move forward with constant velocity as they fall
When a certain person steps onto a scale on solid ground, the reading is 750N. When the same person rides in an elevator that accelerates, the reading on the scale is different. Rank the three cases (A, B, and C) shown in Figure 5-18 in order of increasing acceleration (from most negative to most positive) in the y direction. Indicate ties where appropriate
B < A < C
A system consists of an object with mass m and speed υ that moves on a circular path with a radius of curvature r. Rank the following systems (A, B, C, D) in order of in creasing centripetal force required to cause the motion. Indicate ties where appropriate A: m=1kg,υ=5m/s,r=5m B: m=6kg,υ=1m/s,r=2m C: m=6kg
B < A < D < C
The figure shows four identical bricks that are at rest on surfaces tilted at different angles. Rank the bricks in order of increasing normal force exerted on them by the surface. Indicate ties where appropriate
B = C < D < A
A ball is thrown straight up, reaches a maximum height, then falls to its initial height. Select the correct statement about the direction of the velocity and acceleration as the ball is coming down
Both its velocity and acceleration point downward
A mass is attached to one end of a string. The other end of the string is attached to a rigid support. The mass is released at A and swings in a vertical arc to points B, C, and D, as shown below. At what point does the mass have its highest speed?
C
Rank the instantaneous velocity of the object at points A, B, C, and D in order of increasing velocity, from most negative to most positive
C < B < D < A
The stretch of a spring and the force it exerts are inversely proportional
False
The area under a curve in a velocity versus time graph gives
Displacement
A dog is standing in the bed of a pickup truck. The bed is coated with ice, causing the force of friction between the dog and the truck to be zero. The truck is initially at rest, and then accelerates to the right, moving along a flat road. As seen from a stationary observer (watching the truck move to the right), the dog
Does not move left or right, but the back of the truck moves towards the dog
You swing a bat and hit a heavy box with a force of 1500 N. The force the box exerts on the bat is
Exactly 1500 N whether or not the box moves
A body moving with constant speed cannot be accelerating
False
A car is being towed at constant velocity on a horizontal road using a horizontal chain. The tension in the chain must be equal to the weight of the car in order to maintain constant velocity
False
A system that has zero momentum must also have zero kinetic energy
False
An object moving along a curved path with constant speed does not have a net force acting on it
False
In order to get an object moving, you must push harder on it than it pushes back on you
False
When a mass is attached to a certain spring, the spring stretches by the amount x. Suppose we now connect two of these springs together in series. If we attach the same mass to this system, is the amount of stretch greater than, less than, or equal to x? Explain
Greater than x. Each of the springs stretches by the amount x, and hence the total stretch is 2x
If the net work done on an object is positive, then the object's kinetic energy
Increases
An object is moving to the right, and experiencing a net force that is directed to the right. The magnitude of the force is decreasing with time. The speed of the object is
Increasing
When an object experiences uniform circular motion, the direction of the net force is
Is directed toward the center of the circular path
For general projectile motion, the horizontal component of a projectile's acceleration
Is zero
For general projectile motion, which statement is true when the projectile is at the highest point of its trajectory?
Its velocity is perpendicular to the acceleration
A stone is thrown straight up. When it reaches its highest point,
Its velocity is zero and its acceleration is not zero
Suppose a ball is thrown straight up, reaches a maximum height, then falls to its initial height. Select the correct statement about the direction of the velocity and acceleration as the ball is going up
Its velocity points upward and its acceleration points downward
An object is acted on by a single force that is at an angle of 35° above the positive x axis. The object's x component of acceleration is 1m/s2. Is the y component of the object's acceleration greater than, less than, or equal to 1m/s2? Explain
Less than 1m/s2 because the y component of a vector is less than the x component when the vector is only 35° above the x axis
A ball drops some distance and loses 30 J of gravitational potential energy. Do NOT ignore air resistance. How much kinetic energy did the ball gain?
Less than 30 J
In the absence of an external force, a moving object will
Move with constant velocity
If the velocity versus time graph of an object is a straight line making an angle of 30 degrees with the time axis, the object is
Moving with constant non-zero acceleration
A student kicks a soccer ball in a high arc toward the opponent's goal. At the highest point in its trajectory
Neither the ball's velocity nor its acceleration is zero
A Ping-Pong ball moving east at a speed of 4 m/s, collides with a stationary bowling ball. The Ping-Pong ball bounces back to the west, and the bowling ball moves very slowly to the east. Which object experiences the greater magnitude impulse during the collision?
Neither; both experienced the same magnitude impulse
You are standing in a moving bus, facing forward, and you suddenly fall forward as the bus comes to an immediate stop. The force acting on you that causes you to fall forward is
No forces were acting on you to cause you to fall
Can work be done on a system if there is no motion?
No, since work involves a non-zero displacement
A baseball player throws a ball to another player. The initial speed of the ball is and it is thrown at an angle of 45° above the horizontal. Is there ever a time during its flight to the other player when its speed is ½v0? Explain
No. The minimum speed is vx=v0cos45°=0.7v0, which is greater than 0.5v0
For general projectile motion, the horizontal component of a projectile's velocity
Remains a non-zero constant
For general projectile motion, the vertical component of a projectile's acceleration
Remains a non-zero constant
If you push twice as hard against a stationary brick wall, the amount of work you do
Remains constant at zero
When a car goes around a curve, it has a tendency to skid outwards. Is the frictional force between the tires and the ground that keeps the car from skidding kinetic or static?
Static
Three boxes are connected by ropes and pulled across a smooth, horizontal surface with an acceleration a. The force applied to the first box on the right is F, the tension in the rope connecting the first and second boxes is T1, and the tension in the rope connecting the second and third boxes is T2. Rank the three forces (F, T1, T2) in order of increasing magnitude. Indicate ties where appropriate
T2 < T1 < F
A submerged alligator swims directly toward two unsuspecting ducks. The equation of motion of the alligator is xa=(0.25 m/s2)t2 , the equation of motion of duck 1 is xd1=3 m−(1.5 m/s)t , and the equation of motion of duck 2 is xd2=3 m+(1 m/s)t . Which duck does the alligator encounter first?
The alligator encounters duck 1 first
Jacques and George meet in the middle of a lake while paddling in their canoes. They come to a complete stop and talk for a while. When they are ready to leave, Jacques pushes George's canoe with a force to separate the two canoes. What is correct to say about the final momentum and kinetic energy of the system?
The final momentum is zero kgm/s but the final kinetic energy is positive
A force F pushes on three boxes that slide without friction on a horizontal surface. Box 1 has a mass of 1 kg, box 2 has a mass of 2 kg, and box 3 has a mass of 3 kg. The boxes are in contact, and slide as a group with an acceleration a. Is the magnitude of the force of contact between boxes 1 and 2 greater than, less than, or equal to the magnitude of the force of contact between boxes 2 and 3? Explain
The force of contact between boxes 1 and 2 is greater than the force of contact between boxes 2 and 3. The reason is that the force between 1 and 2 must give an acceleration a to a mass of 2kg+3kg=5kg, but the force between 2 and 3 must give an acceleration a to a mass of only 3kg
A 20-ton truck collides with a 1500-lb car and causes a lot of damage to the car. During the collision
The force of on the truck due to the collision is exactly equal to the force on the car
Two objects, one of mass m and the other of mass 2m, are dropped from the top of a building. When they hit the ground
The heavier one will have twice the kinetic energy of the lighter one
Is the instantaneous velocity at t=0.500s greater than, less than, or the same at the instantaneous velocity at t=1.00s?
The instantaneous velocity is greater at t=0.500s
If the acceleration vector of an object is directed anti-parallel to the velocity vector,
The object is slowing down
If the acceleration vector of an object is directed parallel to the velocity vector,
The object is speeding up
If the acceleration vector of an object is directed perpendicular to the velocity vector,
The object is turning
Consider a plot of the displacement (x) as a function of the applied force (F) for an ideal elastic spring. The slope of the curve would be
The reciprocal of the spring constant
Suppose the tension in the clothesline is 120 N. Is the sag angle greater than, less than, or equal to 3.50°? Explain
The sag angle is greater, because with a smaller tension (120 N versus 148 N) a larger vertical component is required to support the weight. This in turn requires a larger angle
A girl throws a stone from a bridge. Consider the following ways she might throw the stone. The speed of the stone as it leaves her hand is the same in each case, and air resistance is negligible. Case A: Thrown straight up Case B: Thrown straight down Case C: Thrown out at an angle of 45º above horizontal Case D: Thrown straight out horizontally In which case will the speed of the stone be greatest when it hits the water below?
The speed will be the same in all cases
A 3.0-kg object moves to the right at 4.0 m/s. It collides head-on with a 6.0-kg object moving to the left at 2.0 m/s. Which statement is correct?
The total momentum both before and after the collision is zero
A ball is tossed vertically upward. When it reaches its highest point (before falling back downward)
The velocity is zero, the acceleration is directed downward, and the force of gravity acting on the ball is directed downward
A net horizontal force is required for a body to move in a horizontal circle
True
An ideal pulley changes the direction of the tension in a string without changing its magnitude
True
If a force always acts perpendicular to an object's direction of motion, that force cannot change the object's kinetic energy
True
The center of mass of an object does not have to be located within the object
True
The force of static friction between two surfaces is independent of the area of contact between the surfaces
True
The force of static friction between two surfaces is parallel to the surface of contact, and in the direction that opposes relative motion
True
Vector quantities are represented in terms of their magnitude and direction
True
When an object is solely under the influence of conservative forces, the sum of its kinetic and potential energies does not change
True
Consider what happens when you jump up in the air. Which of the following is the most accurate statement?
When you push down on the earth with a force greater than your weight, the earth will push back with the same magnitude force and thus propel you into the air
On a force vs. position graph, the area under curve is a representation of
Work
Is it possible for two vectors to be different from one another, but still have the same magnitude?
Yes, if the vectors point in different directions
Is it possible for a system to have negative potential energy?
Yes, since the choice of the zero of potential energy is arbitrary
The acceleration of an object has a magnitude a. What is the magnitude of the acceleration in the following cases? a) All the forces acting on the object are doubled b) The mass and the net force acting on the object are doubled c) The net force acting on the object is doubled, and its mass is halved d) The mass of the object is doubled, and the net force acting on it is halved
a) 2a b) a c) 4a d) a/4
A vector has the components Ax=5 m and Ay=3m a) Is the magnitude of →A greater than, less than, or equal to 8 m? Explain. b) Is the direction angle of →A greater than, less than, or equal to 45°? Explain.
a) Less than 8 m because the x and y components are at right angles to one another b) Less than 45° because the vertical side of the corresponding triangle is shorter than the horizontal side
Two objects, A and B, are launched horizontally. The horizontal distance covered before landing is smaller for object A than for object B a) Is the initial speed of object A greater than, less than, or equal to the initial speed of object B? Explain b) Is the amount of time object A is in the air greater than, less than, or equal to the time object B is in the air? Explain
a) Less, because object A covers a smaller horizontal distance b) The times are equal because the objects fall through the same vertical distance
For each of the following questions, give an example if your answer is yes. Explain why not if your answer is no a) Is it possible to take a trip in which the distance covered is less than the magnitude of the displacement? b) Is it possible to take a trip in which the distance covered is greater than the magnitude of the displacement?
a) No. Distance is always increasing on a trip, whereas the magnitude of displacement can increase or decrease b) Yes
A projectile is launched and lands at the same level, as shown in Figure 4-12. Three points during the flight of the projectile are indicated in the figure a) Which of the four velocity vectors (shown in green) corresponds to points 1, 2, and 3? b) Which of the four acceleration vectors (shown in purple) corresponds to points 1, 2, and 3?
a) Point 1, vector A; point 2, vector C; point 3, vector B b) Points 1 through 3, vector G
For the time intervals between (a) points 1 and 2, (b) points 2 and 3, and (c) points 3 and 4, state whether the average velocity is positive, negative, or zero
a) Positive b) Zero c) Negative
At a certain time, object 1 has an initial velocity of −2 m/s and an acceleration of 3 m/s2. At the same time, object 2 has an initial velocity of 5 m/s and an acceleration of −1 m/s2 a) Is the speed of object 1 increasing or decreasing? Explain b) Is the velocity of object 1 increasing or decreasing? Explain c) Is the speed of object 2 increasing or decreasing? Explain d) Is the velocity of object 2 increasing or decreasing? Explain
a) The speed is decreasing because velocity and acceleration have opposite signs b) The velocity is increasing (becoming less negative) because the acceleration is positive c) The speed is decreasing because velocity and acceleration have opposite signs d) The velocity is decreasing (becoming less positive) because the acceleration is negative
The equations of motion of an object are x=(1m/s2)t2 and y=(2m)−(3m/s)t. What are the x and y components of the object's a) initial position b) initial velocity c) acceleration
a) x0=0, y0=2m b) v0x=0, v0y=3m/s c) ax=2m/s2, ay=0
The equation of motion for an object moving with constant acceleration is x=6 m−(5 m/s)t+(4 m/s2)t2 a) What is the position of this object at t=0? b) What is the velocity of this object at t=0? c) What is the acceleration of this object?
a) x=6 m b) v=−5m/s c) a=8m/s
Several vectors are shown in the figure. The red vectors have a magnitude equal to a diagonal across the square formed by the blue vectors. Which of the given vectors represents the following quantities: a) →A+→B b) →D−→A c) →G−→C d) →B+→H−→D
a) →F b) →H c) →B d) →G
Give the dimensions of each of the following quantities (a, b, c, d), given that x is a distance, v is a velocity, a is an acceleration, and t is a time: a= at, b= v/t, c= 0.5x/t^2, d= 2ax
a= [L]/[T] b= [L]/[T^2] c= [L]/[T^2] d= [L^2]/[T^2]
Which of the following statements is correct? a) A net force is required to keep an object moving with constant velocity b) A net force is required to make an object accelerate c) When you hit the brakes in a car, a force pushes you toward the front of the car d) When you accelerate in a car, a force pushes you back into your seat e) An object that is moving will continue to move with the same velocity unless a net force acts on it
b) A net force is required to make an object accelerate e) An object that is moving will continue to move with the same velocity unless a net force acts on it
Two forces have magnitudes F1 and F2. If these forces are added together, which of the following statements about the net force is correct? a) The net force must have a magnitude equal to F1+F2 b) The net force can have a magnitude less than F1+F2 c) The net force can have a magnitude greater than F1+F2 d) The net force has a magnitude greater than F1
b) The net force can have a magnitude less than F1+F2
Which, if any, of the following statements concerning the work done by a conservative force is NOT true? a) It can always be expressed as the difference between the initial and final values of a potential energy function b) When the starting and ending points are the same, the total work is zero c) It is independent of the path of the body and depends only on the starting and ending points d) All of these statements are true
d) All of these statements are true
The laws of physics apply to which of the following: a) Gravity b) Electricity c) Magnetism d) Light e) Atoms f) All of these
f) All of these
Swimmers at a water park have a choice of two frictionless water slides (see Figure 8-2). 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 end of slide 1 compares with v2, the speed of a swimmer reaching the end of slide 2?
v1=v2