Physics final review set 1

Two billiard balls having the same mass and speed roll toward each other. What is their combined momentum after they meet?

0

An apple at rest weighs 1 N. The net force on the apple when it is in free fall is

1 N.

An object is dropped and freely falls to the ground with an acceleration of 1 g. If it is thrown upward (neglecting air-resistance) at an angle instead, its acceleration will be

1 g downward.

A 1-kg chunk of putty moving at 1 m/s collides with and sticks to a 5-kg bowling ball initially at rest. The bowling ball and putty then move with a momentum of

1 kg m/s.

A 5 kg ball has a acceleration of 2 m/s2. The the magnitude of the force responsible for producing this acceleration is

10 N

The force of friction on a sliding object is 10 N. The applied force needed to maintain a constant velocity is

10 N.

The weight of a 1-kg mass at the earths surface us about

10N

An object at rest near the surface of a distant planet starts to fall freely. If the acceleration due to gravity there is twice that of the Earth, its speed one second later would be

20 m/s.

A ball is thrown upwards from the surface of the earth at the speed of 10 m/s. It returns to the same position. How kong does it stay in the air (neglect the air resistance) ?

2s

A 4 kg ball has a momentum of 12 kg m/s. What is the ball's speed?

3 m/s

Ten seconds after starting from rest, a car is moving at 40 m/s. What is the car's acceleration

4.0 m/s2

A TV set is pushed a distance of 2 m with a force of 20 N. How much work is done on the set?

40 J

A man weighing 1000 N stands at rest on two bathroom scales so that his weight is distributed evenly over both scales. The reading on each scale is

500

A person is attracted toward the center of Earth by a 500-N gravitational force. The Earth is attracted toward the person with a force of

500 N.

A 10-N falling object encounters 4 N of air resistance. The net force on the object is

6 N.

An object in mechanical equilibrium is an object

A) at rest.B) moving with constant velocity.C) having no acceleration. D) all of these Answer: D

What task requires the most work; lifting a 50-kg sack 2 meters or lifting a 25- kg sack 4 meters?

Both require the same amount of work.

An object is somehow propelled along a straight-line its path by a force. If the mass of the object somehow becomes twice as much, its acceleration

Halves

Whenever the net force on an object is zero, its acceleration

Is zero

A kilogram is a measure of an object's

Mass

Which is the following is not a vector quantity?

Mass

A rock is thrown straight up from the surface of the Earth. Which one of the following statements describes the energy transformation of the rock as it rises? Neglect air resistance.

The kinetic energy decreases and the potential energy increases.

While an object near the earths surface is in free fall, its

Velocity increases

In science, a theory is -------

a synthesis of a large body of well-tested knowledge

The mass of a pet turtle that weighs 10 N is

about 1 kg.

The famous Leaning Tower of Pisa doesn't topple over because its center of gravity is

above a place of support.

A baseball bat is balanced on a fulcrum. The center of gravity of the bat is located

above the fulcrum.

Disregarding air resistance, objects fall with constant

acceleration.

If the mass of an object does not change, a constant net force on the object produces constant

acceleration.

Compared to a 1-kg block of solid iron, a 2-kg block of solid iron has twice as much ----

all of these

Inside a freely falling elevator, there would be no

apparent weight for you.

If the Earth had two identical moons in one circular orbit, and the moons were as far apart in that orbit as they could be, the center of gravity of the Earth-moons system would be

at the center of the Earth.

Neglecting friction, a large block of ice and a small block of ice start sliding down an incline together. The heavier block will get to the bottom

at the same time as the light block.

Toss a baseball bat into the air and it wobbles about its

center of mass.

If an object moves with constant acceleration, its velocity must

change by the same amount each second.

If no external forces are acting on a moving object, it will

continue moving at the same velocity.

A rock is thrown upward at 50 degrees with respect to the horizontal. As it rises, neglecting air drag, its vertical component of velocity

decreases.

A skydiver jumps from a high-flying plane. As her velocity of fall increases, her acceleration

decreases.

The stretching out of time due to motion is called time

dilation.

The two measurements necessary for calculating average speed are ------

distance and time.

According to Newton, doubling the distance between two interacting objects

divides by 4 the gravitational force between them.

A freight train rolls along a track with considerable momentum. If it rolls at the same speed but has twice as much mass, its momentum is

doubled.

The acceleration due to gravity acts:

downward

According to Kepler's laws, the paths of planets about the sun are

ellipses.

A popular swinging-balls apparatus consists of an aligned row of identical elastic balls that are suspended by strings so they barely touch each other. When two balls are lifted from one end and released, they strike the row and two balls pop out from the other end. If instead one ball popped out with twice the speed of the two, this would be a violation of conservation of

energy.

A rock is thrown vertically into the air. At the very top of its trajectory the net force on it is

equal to its weight.

A player hits a ball with a bat. The action force is the impact of the bat against the ball. The reaction to this force is the

force that the ball exerts on the bat.

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

force the glove exerts on the ball.

The newton (N) is a unit of

force.

An Earth satellite is simply a projectile

freely falling around the Earth.

When you approach a blinking light source which in turn is moving towards you, you perceive an increase in

frequency of the light, but not speed.

According to Newton, the greater the masses of interacting objects, the

greater the gravitational force between them.

A heavy truck and a small car rolling down a hill at the same speed are forced to stop in the same amount of time. Compared to the force that stops the car, the force needed to stop the truck is

greater.

An object following a straight-line path at constant speed

has zero acceleration.

When an automobile is braked to a stop, its kinetic energy is transformed to

heat.

A heavy rock and a light rock of the same size are falling through the air from a tall building. The one that encounters the greatest air resistance is the

heavy rock.

A bullet is fired horizontally from a gun. At the same time a similar bullet is dropped from the same height. The fired bullet will (neglect air-resistance)

hit at the same time as the dropped bullet

If a non-rotating object has no acceleration, then we can say for certain that it is

in mechanical equilibrium.

If an object's mass is decreasing while a constant force is applied to the object, the acceleration

increases.

When a twirling ice skater brings her arms inward, her rotational speed

increases.

In each second of fall, the distance a freely falling object will fall is

increasing.

Two tennis balls fall through the air from a tall building. One of them is filled with lead pellets. In presence of air-resistance, the ball to reach the ground first is the --

lead-filled ball.

Two objects have the same size and shape, but one is much heavier than the other. When they are dropped simultaneously from a tower, they reach the ground at the same time, but the heavier one has a greater

momentum.

The reason the moon does not crash into the Earth is that the

moon has a sufficient tangential speed.

An object that has kinetic energy must be

moving.

An Earth satellite is in an elliptical orbit. The satellite travels fastest when it is

nearest the Earth.

If you push for a half hour or a whole hour against a stationary wall

no work on the wall is done in either case.

While a car travels around a circular track at a constant speed, its

none of the above

An object may have potential energy because of its

position.

To outside observers, the overall sizes of objects traveling at relativistic speeds are

smaller.

A ring, a cylinder, and a solid sphere begin rolling down a hill together. Given that the rotational inertia of the solid sphere is the least and that of the ring is the most , the one to reach the bottom first is the

sphere.

Compared to falling on a stone floor, a wine glass may not break when it falls on a carpeted floor because the

stopping time is longer on the carpet.

The center of mass of a human body is located at a point

that changes as a person bends over.

Which has greater kinetic energy, a car traveling at 30 km/hr or a car of half the mass traveling at 60 km/hr?

the 60 km/hr car

A ball rolling down an incline has its maximum kinetic energy at

the bottom.

A block of ice sliding down an incline has its maximum speed at

the bottom.

It is correct to say that impulse is equal to

the change in momentum it produces.

Your weight is

the gravitational attraction force between you and the Earth.

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

the milk carton has inertia.

If more horizontal force is applied to a sliding object than is needed to maintain a constant velocity

the object accelerates in the direction of the applied force.

5) A ball is thrown upwards and returns to the same position. Compared with its original speed after release, its speed when it returns is about

the same

A car traveling at 100 km/hr strikes an unfortunate bug and splatters it. The force of impact is

the same for both.

A ball is thrown upwards and returns to the same position. Compared with its original speed after release, its speed when it returns is about --------

the same.

A golfer drives her golf ball from the tee down the fairway in a high arcing shot. When the ball is at the highest point of its flight:

the x-velocity is non-zero and the y-velocity is zero

If an object is raised twice as high, its potential energy will be

twice as much.

Passengers in a high-flying jumbo jet feel their normal weight in flight, while passengers in the orbiting space shuttle do not. This is because passengers in the space shuttle are

without support forces.

1) Scientific hypothesis may turn out to be right or it may turn out to be wrong. If it is a valid hypothesis, there must be a test for proving it---

wrong.

When a falling object has reached its terminal velocity, its acceleration is

zero.