Physics Unit 2

c. is the same for both

A Mack truck and a Volkswagen traveling at the same speed collide head-on. The impact force is greatest on the a. Volkswagen b. Mack truck c. is the same for both

b. less than 100 J

A ball is projected into the air with 100 J of kinetic energy that is transformed to gravitational potential energy at the top of its trajectory. When it returns to its original level after encountering air resistance, its kinetic energy is a. 100 J b. less than 100 J c. more than 100 J d. not enough information is given

b. 45 m

A ball is thrown horizontally from the top of a tall cliff. Three seconds later, the ball has fallen a vertical distance of a. 20 m b. 45 m c. 30 m d. depends on the initial horizontal speed of the ball

c. less than the speed it had when thrown upwards

A ball is thrown upwards and caught when it comes back down. In the presence of air resistance, the speed with which it is caught is a. the same as the speed it had when thrown upwards b. more than the speed it had when thrown upwards c. less than the speed it had when thrown upwards

c. the same as the speed it had when thrown upwards

A ball is thrown upwards and caught when it comes back down. Neglecting air resistance, the speed with which it is caught is a. less than the speed it had when thrown upwards b. more than the speed it had when thrown upwards c. the same as the speed it had when thrown upwards

b. 14 m/s

A ball rolls off the edge of a horizontal roof at a velocity of 10 m/s. One second later, the speed of the ball is about a. 20 m/s b. 14 m/s c. 16 m/s d. 10 m/s

a. 6 N

A block is dragged without acceleration in a straight-line path across a level surface by a force of 6 N. What is the force of friction between the block and the surface? a. 6 N b. more than 6 N c. less than 6 N d. need more information to say

.b. accelerations

A feather and a coin dropped in a vacuum fall with equal a. forces b. accelerations c. momenta d. kinetic energies e. none of these

a. ratio of force to mass is the same

A heavy rock and a light rock in free fall have the same acceleration. The reason the heavy rock doesn't have a greater acceleration is that the a. ratio of force to mass is the same b. force due to gravity is the same on each c. air resistance is always zero in free fall d. inertia of both tocks is the same

d. a value between zero and g

A math book and a physics book are tied together with a length of string. With the string taut, one book is pushed off the edge of a table. As it falls, the other book is dragged horizontally across the table surface. With no friction, acceleration of the books is a. the force required to stop it b. g/2 c. a value that could be greater than g d. a value between zero and g e. g

e. none of these

Consider two planets in space that gravitationally attract each other. If the masses of both planets is doubled, and the distance between them is also doubled, then the force between them is a. four times as much b. twice as much c. half as much d. one-quarter e. none of these

b. 10 m/s

Disregarding air drag, how fast must you toss a ball straight upward in order to remain in the air for a total time of 2 s? a. 20 m/s b. 10 m/s c. 15 m/s d. 7.5 m/s e. 5 m/s

c. acceleration

Disregarding air resistance, objects fall at constant a. speed b. velocity c. acceleration d. distances each successive second

b. the same

Drop a rock from a 5-m height and it accelerates at 10 m/s/s and strikes the ground 1 s later. Drop the same rock from a height of 2.5 m and its acceleration of fall is a. more b. the same c. about half

a. extra high

During an eclipse of the Sun, the high ocean tides on Earth are a. extra high b. extra low c. not particularly different

c. both of these

Earth pulls on the Moon. Similarly, the Moon pulls on Earth, evidence that a. Earth's and Moon's pulls comprise an action-reaction pair b. Earth and the Moon are simply pulling on each other c. both of these

d. Forget it, you can't travel far enough

How far must one travel to get away from the Earth's gravitational field? a. to a region beyond the solar system b. to a region well beyond the Moon. c. to a region above the Earth's atmosphere d. Forget it, you can't travel far enough

a. momentum

What does an object have when moving that it doesn't have when at rest a. momentum b. inertia c. energy d. mass e. none of these

b. outward from the paper

What is the direction of the angular velocity for a cylinder in problem 15, figure d, which rotates around the axes orthoganol to the paper? a. inward from the paper b. outward from the paper c. upward d. downward e. to the right

b. 500 N

What is the force of gravity on a 500 N woman standing on the earth's surface? a. 250 N b. 500 N c. 50 N d. 509.8 N e. none of these

e. the body is in equilibrium

When the sum of the external forces and the sum of the external torques on a body are both zero, we can conclude that a. the body is moving at constant velocity but is not rotating b. the body is rotating at constant angular velocity but has no linear velocity c. the body has neither linear nor angular velocity d. the body may have constant linear or angular velocity, but not both simultaneously e. the body is in equilibrium

e. 5 J

A 1 kg ball dropped from a height of 2 m rebounds only 1.5 m after hitting the ground. The amount of energy converted to heat is about a. 10 J b. 20 J c. 15 J d. 0.5 J e. 5 J

a. 100 J

A person on the edge of a roof throws a ball downward. It strikes the ground with 100 J of kinetic energy. The person throws another identical ball upward with the same initial speed, and this too falls to the ground. Neglecting air resistance, the second ball hits the ground with a kinetic energy of a. 100 J b. less than 100 J c. more than 100 J d. 200 J e. none of these

d. force the glove exerts on the ball

A player catches a ball. Consider the action force to be the impact of the ball against the player's glove. The reaction to this force is the a. friction of the ground against the player's shoes b. player's grip on the glove c. muscular effort in the player's arms d. force the glove exerts on the ball

d. is not acted on by any horizontal force

A projectile is fired horizontally in a region of no air resistance. The projectile maintains its horizontal component of speed because it a. has no vertical component of speed to begin with b. is not acted on by any force c. the net force acting on it is zero d. is not acted on by any horizontal force e. none of these

b. 40 degrees

A projectile is thrown into the air at an angle of 50 degrees and lands on a target that is at the same level the projectile started. It will also land on the target if it is thrown at an angle of a. 45 degrees b. 40 degrees c. 55 degrees d. 60 degrees e. none of these

d. the milk carton has inertia

A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked quickly. This best demonstrates that a. gravity tends to hold the milk carton secure b. there is an action-reaction pair of forces c. the milk carton has no acceleration d. the milk carton has inertia

c. 5 m

A stone is thrown horizontally from the top of a cliff. One second after it has left your hand its vertical distance below the cliff is a. 10 m b. 15 m c. 5 m

a. 160 J

A toy cart moves with a kinetic energy of 40 J. If it moves with twice the speed, its energy will be a. 160 J b. 40 J c. 80 J d. unknown unless we know the mass of the cart

c. Both forces are the same

A very massive object A and a less massive object B move toward each other under the influence of gravitation. Which force, if either is greater? a. the force on A b. the fouce on B c. Both forces are the same

a. 100 N

A woman who normally weighs 400 N stands on top of a very tall ladder so she is one Earth-radius above the earth's surface. How much would she weigh there? a. 100 N b. 400 N c. zero d. 200 N e. none of these

a. a single interaction

Action and reaction forces compose the parts of a. a single interaction b. two interactions

a. double

An object is propelled along a straight-line path by a force. If the net force were doubled, its acceleration would a. double b. quadruple c. stay the same d. halve e. none of these

a. velocity increases

As an object freely falls, its a. velocity increases b. acceleration increases c. both of these d. none of these

a. 100 kg

Careful: On the surface of Jupiter, where the acceleration due to gravity is about three times of Earth, a 100-kg rock would have a mass of about a. 100 kg b. 600 kg c. 300 kg d. 900 kg

a. the mass should be concentrated at the outer edge of the body

How should the mass of a rotating body of radius r be distributed to minimized its angular velocity? a. the mass should be concentrated at the outer edge of the body b. the mass should be evenly distributed throughout the body c. the mass should be concentrated at the axis of rotation d. the mass should be concentrated at a point midway between the axis of rotation and the outer edge of the body e. mass distribution has no impact on angular velocity

c. decrease to one-half your original weight

If Earth's mass decreased to one-half its original mass with no change in radius, then your weight would a. decrease to one-quarter your original weight b. stay the same c. decrease to one-half your original weight d. none of these

c. continually change by the same amount each second

If an object falls with constant acceleration, the velocity of the object must a. be constant also b. continually change by varying amounts, depending on its speed c. continually change by the same amount each second d. continually decrease e. none of these

false

If an object stops moving at a point, then its acceleration must be zero at that point. true or false

true

If the "velocity versus time" graph of an object is a horizontal line, that object cannot be accelerating. true or false

e. the net torque acting on the object is zero

If the angular acceleration of a rigid body is zero, it must necessarily be true that a. the angular velocity is constant b. the net force acting on the object is zero c. the angular velocity is zero d. the angular momentum is zero e. the torque acting on the object is zero

a. acceleration

If the mass of an object does not change, a constant bet force on the object produces constant a. acceleration b. velocity c. both of these d. none of these

b. momentum

If the speed of a moving object doubles, then what else doubles? a. kinetic energy b. momentum c. acceleration d. A and B are both correct e. none of these

b. kilogram

If you are measuring the mass of an elephant, the most appropriate SI unit is the a. centigram b. kilogram c. gram d. milligram e. microgram

d. increasing

In each second of fall, the distance a freely falling object will fall is a. the same, but not 5 m or 10 m b. about 10 m c. about 5 m d. increasing e. none of these

true

It is not physically possible for the "position versus time" graph of a moving animal to be either perfectly vertical or perfectly horizontal true or false

false

It is physically impossible for an object to have a negative acceleration and yet be speeding up. true or false

a. force

Moment of inertia is the rotational analog of mass. Torque is the rotational analog of a. force b. acceleration c. mass d. momentum e. kinetic energy

b. that gravity is universal

Newton discovered a. gravity b. that gravity is universal c. neither

d. the force on the ball is at right triangles to the ball's motion

No work is done by gravity on a bowling ball that rolls along a bowling alley because a. no distance is covered by the ball b. no potential energy is being converted to kinetic energy c. its kinetic energy remains constant d. the force on the ball is at right triangles to the ball's motion e. no force acts on the ball

d

Pairs of forces of equal magnitude act on identical cylinders as shown in the figures. In which figure the cylinder is not in translatory equilibrium? a b c d e

a. remains constant

Roll a bowling ball off the edge of a table. As it falls, its horizontal component of motion a. remains constant b. increases c. decreases

a. conservation of angular momentum

Stars originate as large bodies of slowly rotating gas. Because of gravity, these clumps of gas slowly decrease in size. The angular velocity of a star increases as it shrinks because of a. conservation of angular momentum b. conservation of linear momentum c. conservation of energy d. the law of universal gravitation e. conservation of mass

d. continues at the speed it had when it encountered the second force

Suppose a particle is being accelerated through space by a 10-N force. Suddenly the particle encounters a second force of 10 N in the opposite direction of the first force. The particle with both forces acting on it a. theoretically tends to accelerate toward the speed of light b. decelerates gradually to a halt c. is brought to a rapid halt d. continues at the speed it had when it encountered the second force e. none of these

a. astronaut will never catch the first bounce

Suppose an astronaut in outer space wishes to play a solitary "throw, bounce, and catch" game by tossing a ball against a very massive and perfectly elastic concrete wall. If the ball is as massive as the astronaut, the a. astronaut will never catch the first bounce. b. astronaut will catch one bounce only. c. astronaut's time between catches will decrease as the game progresses. d. none of these

d. kg m^2/s

The SI units of angular momentum are a. kg m/s^2 b. kg m^2/s^2 c. rad/s^2 d. kg m^2/s e. kg m/s

true

The acceleration is always the slope of the "velocity versus time" graph and the velocity is always the slope of the "position versus time" graph

e. only a or b above is staisfied

The center of gravity of an object is at the same position as the center of mass when a. the object is so far from any mass that approximately g = 0 b. the object is located in a region where g is uniform over the entire object c. the object is as large as the body that exerts the gravitational force on it d. any of the conditions above is satisfied e. only a or b above is satisfied

D. the second and third law

The conservation of momentum is most closely related to a. newtons second law b. newtons third law c. newtons first law d. the second and third law

d. the acceleration of the car is positive and decreasing

The figure shows the velocity versus time graph for a car driving on a straight road. Which of the following best describes the acceleration of the car? a. the acceleration of the car is constant b. the acceleration of the car is negative and decreasing c. the acceleration of the car is positive and increasing d. the acceleration of the car is positive and decreasing e. the acceleration of the car is negative and increasing

b. zero

The force required to maintain an object at a constant velocity in free space is equal to a. the force required to stop it b. zero c. the mass of the object d. the weight of the object

c. 10 m/s

The gain in speed each second for a freely falling object is about a. 0 b. 20 m/s c. 10 m/s d. 5 m/s e. depends on the initial speed

d. about 5000 N

The human body can, under certain conditions, withstand an acceleration of 10g. What net force would produce this acceleration on a 50-kg person? a. about 2500 N b. about 25,000 N c. about 500 N d. about 5000 N

a. is greater on oceans closer to the Moon and less on oceans farther from the Moon

The main reason ocean tides exist is that the pull of the Moon a. is greater on oceans closer to the Moon and less on oceans farther from the Moon b. and the Sun on the oceans are in opposite directions c. and Sun are in conjunction at high tides and in opposition at low tides d. is greater on the earth because the Moon is closer to Earth e. none of these

d. the Moon has a sufficient tangential speed

The reason the Moon does not crash into Earth is that a. Earth's gravitational field is weak at the Moon b. the gravitational pull of other planets keeps the Moon up c. the Moon has less mass than Earth d. the Moon has a sufficient tangential speed e. none of these

c. all parts of it are practically the same distance from the Moon

There are no tides to be seen in the community swimming pool because a. it is shallow compared to the ocean b. gravitation on the small mass of water is negligibly small c. all parts of it are practically the same distance from the Moon d. they are masked by the much stronger pull of Earth gravity e. but there are, at nighttime

b. 0 kg m/s

Two billiard balls having the same mass roll toward each other, each moving at the same speed. What is the combined momentum of the two balls? a. 10 kg m/s b. 0 kg m/s c. more information is needed to determine

b. four times as far as the slower arrow

Two identical arrows, one with twice the speed of the other, are fired into a hay bale. The faster arrow will penetrate a. twice as far as the slower arrow b. four times as far as the slower arrow c. more than four times as far as the slower arrow d. the same distance as the slower arrow e. none of these

b. increases

Two objects move toward each other because of gravity. As the objects get closer and closer, the acceleration of each a. decreases b. increases c. remains constant

e. the angular velocity of A is greater than that of B

Two points are located on a rigid wheel that is rotating with a decreasing angular velocity about a fixed axis. Point A is located on the rim of the wheel and point B is halfway between the rim and the axis. Which one of the following is not true concerning this situation? a. A has a greater centripetal acceleration than B b. A has a greater tangential velocity than B c. Both points have the same instantaneous angular velocity d. each second, A turns through the same angle as B e. the angular velocity of A is greater than that of B

d. has a wider handle

Using a screwdriver, you try to remove a screw from a piece of furniture, but can't get it to turn. To increase the chances of success, you should use a screwdriver that a. is longer b. is shorter c. has a narrower handle d. has a wider handle

a. about 10 times

When you jump from an elevated position you usually bend your knees upon reaching the ground. By doing this, the time of the impact is about 10 times more than for a stiff-legged landing. In this way the average force your body experiences is reduced by a. about 10 times. b. less than 10 times. c. more than 10 times.

a. the Moon

Which is most responsible for the ocean tides? a. the Moon b. the Sun c. both contribute equally

e. both a and d

Which of the following is a scalar quantity a. speed b. displacement c. acceleration d. distance e. both a and d

d. it is less than or equal to the distance traveled

Which of the following is always true about the magnitude of the displacement? a. it is greater than the distance traveled b. it is equal to the distance traveled c. it is less than the distance traveled d. it is less than or equal to the distance traveled

b. the Sun

Which pulls on the oceans of Earth with the greater force? a. the Moon b. the Sun c. both pull the same

d. none of these

While a car travels around a circular track at a constant speed, its a. acceleration is zero b. velocity is zero c. both of these d. none of these

c. and the earth circle each other

With respect to the stars, the Moon a. circles the earth b. remains stationary while the earth circles about it c. and the earth circle each other d. does not rotates about it's own axis as the earth does

b. the rate of change of acceleration

the slope of the acceleration vs. time curve represents a. the velocity b. the rate of change of acceleration c. the rate of change of displacement d. the area under the position vs time curve e. cannot be calculated