Physics Midterm 1

A Mack truck and a Volkswagen traveling at the same speed have a head-on collision. The vehicle that undergoes the greatest change in velocity will be the

Volkswagen

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

above a place of support

When you stand at rest on a pair of bathroom scales, the readings on the scales will always:

add up equal to your weight

Hang from a pair of gym rings and the upward support forces of the rings will always:

add up to equal your weight

Your friend says that the heavyweight champion of the world cannot exert a force of 50N on a piece of tissue paper with his best punch. The tissue paper is held in midair - no wall, no tricks. You

agree that it can't be done

According to Newton's law of intertia, a railroad trin in motion should continue going forever even if its engine is turned off. We never observe this because railroad trains:

always have forces that oppose their motion

Two billard balls have the ssame mass and speed roll toward each other. What is thier compined momentum after they meet?

0

It takes 40 J to push a large box 4 m across a floor. Assuming the push is in the same direction as the move, what is the magnitude of the force on the box?

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

An apple falls from a tree and hits the ground 5 meters below. It hits the ground with a speed of about:

10 m/s

A baseball player bats a ball with a force of 1000N. The reaction force that the ball exerts against the bat is

1000N

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

10N

A ball is moving at 3 m/s and has a momentum of 48 kg m/s. What is the ball's mass?

16 kg

A car moves 4 times as fast as another identical car. Compared to the slower car, the faster car has

16 times the KE

A car moving at 50 km/hr skids 20 m with locked brakes. How far will the car skid with locked brakes ifit were traveling at 150 km/hr

180 m

A jumbo jet has a mass of 100,000 kg. The thrust for each of its four engines is 50,000 N. What is the jets acceleration in meters per second per second when taking off?

2

Do 100 J of work in 50 s and your power output is

2 W

A car has a mass of 1000 kg and accelerates at 2 meters per second per second. What is the magnitude of the net force exerted on the car?

2000 N

A horse gallops a distance of 10 kilometers in a time of 30 minutes. Its average speed is:

20km/h

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

3 m/s

A girl pulls on a 10-kg wagon with a constant horizontal force is 30 N. If there are no other horizontal forces, what is the wagon's acceleration in meters per second per second?

3.0

A projectile is launced at ground level an angel of 15 degrees above the horizontal and lands down range. What other projection angle for the same speed would produce the same down-range distance

75 degrees

A 2kg mass is held 4 m above the ground. What is the approximate potential energy of the mass with respect to the ground?

80 J

The scientist to first introduce the concept of intertia was:

Galileo

The attraction of a person's body toward Earth is called weight. The reaction to this force is

The person's body pulling on the Earth

A automobile and a baby carriage traveling at the same speed collide head-on. The impact force is:

The same for both

Which of the following has the largest momentum relative to the Earth's surface?

a pickup truck speeding along a highway

The mass of a pet turtle that weighs 10 N is

about 1 kg

When you jump from an elevated position you usually bend your knees upon reaching the ground. By doing this, you make the time of the impact about 10 times as great as for a stiff-legged landing. In this way the average force your body experiences is:

about 1/10 as great

Horses that move with the fastest linear speed on a merry-go-round are located

near the outside

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

nearest the Earth

An industrial flywheel has a greater rotational inertia when most of its mass is

nearest the rim

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

As a ball falls, the action force is the pull of Earth on the ball. The reaction force is the

pull of the ball's mass on the Earth

A torque acting on an object tends to produce

rotation

It is correct to say that impulse is equal to

the change in momentum it produces

Your weight is

the gravitational attraction between you and the Earth.

If your automobile runs out of fuel while you are driving, the engine stops but you do not come to an abrupt stop. The concept that most explains why is:

inertia

For an action foce, there must be a reaction foce that

is exactly equal in magnitude

The main reason ocean tides exist is that the pull of the moon

is greater on oceans closer to the moon and less on oceans farther from the moon

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

is zero

a projectile is fired horizontally in a region of no air resistance. The projectile maintains its horizontal component of velocity because

it is not acted on by any horizontal forces

An object may have potential energy because of its

location

When you are in the way of a fast-moving object and can't get out of its way, you will suffer a smaller force of impact if you decrease its momentum over a

long time

A force is a vector quantity because is has both:

magnitude and direction

A kilogram is a measure of an object's:

mass

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

mass, inertia, volume, ALL OF THESE

If an object has kinetic energy, then it also must have

momentum

A light woman and a heavy man jump from an airplace at the same time and open their same-size parachutes at the same time. Which person will get to a state of zero acceleration first?

the light woman

A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked quickly. The reason this can be done is that:

the milk carton has inertia

Which is most responsible for the ocean tides

the moon

Compared to the mass of a certain object on Earth, the mass of the same object on the moon is:

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

Earth pulls on the moon. Similarly, the moon pulls on Earth, evidence that:

these two pulls comprise an action-reaction pair

If you do work on an object in one-third the usual time, your power output is

three times the usual power output

To catch a ball, a baseball player the hand forward before impact with the ball and then lets it ride backward in the direction of the ball's motion. Doing this reduces the force of impact on the player's hand principally because the:

time of impact is increased

Without air resistance, a projectile fired horizontally at 8km/s from atop a mountain would

trace a curve that matches the earth's curvature, return later to its starting position and repeat its falling behavior, accelerate downward at g as it moves horizontally, ALL OF THESE

Two identical arrows, one with twice the kinetic energy of the other, are fired into a hay bale. The faster arrow will penetrate

twice as far as the slower arrow

An object is propelled along a straight-line path by a force. If the net force were doubled, the object's acceleration would be

twice as much

If the radius of the Earth somehow decreased with no change in mass, your weight would

increase

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

increases

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

500N

Two objects move toward each other because of gravity. As the objects get closer and closer, the force between them

increases

If one object has twice as much mass as another object, it also has twice as much

inertia

A "weightless" astronaut in an orbiting shuttle is

like the shuttle, pulled by earth's gravitation

If a car increases its velocity from zero to 60km/hr in 10 seconds, its acceleration is:

6 km/hr/s

At one instant an object in free fall is moving downward at 50 m/s. One second later its speed should be about:

60 m/s

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

A large metal ball is shot from a cannon with a short barrel. If the same ball were to be shot from cannon with a longer barrel, its muzzle velocity would be

more

An object that has kinetic energy must be

moving

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

without support forces

A car maintains a constant velocity of 100km/hr for 10 seconds. During this interval its acceleration is:

zero

A hockey puck is set in motion across a frozen pond. If ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is:

zero

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

zero

Earth satellites are typically more than 100 km high so as to be above the Earth's

atmosphere

A bullet fired horizontally over level ground hits the ground in 0.5 second. If it had been fired with twice the speed in the same direction, it would have hit the ground in

0.5 s

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

1 g downward

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

1 kg m/s

Using 1000 J of work, a toy elevator is raised from the ground floor to the second floor in 20 seconds. The power needed to do this job was

50 W

A projectile is launched vertically upward at 50 m/s. If air resistance is negligble, its speed upon returning to its starting point is

50 m/s

A 5000-kg freight car moving at 2 m/s runs into a 10,000kg freight car at rest. They couple upon collision and move away as one body at

2 m/s

suppose the circumference of a bicycle wheel is 2 meters. If it rotates at 1 revolution per second when you are riding the bicycle, then your speed will be

2 m/s

If a rocket initially at rest accelerates at a rate of 50 m/s^2 for one minute, its speed will be:

3000 m/s

A karate chop delivers a blow of 3000N to a board that breaks. The force that acts on the hand during this event is:

3000N

An asteroid exerts a 360-N gravitational force on a nearby spacecraft. If the spacecraft moves to a position three times as far from the center of the asteroid, the force will be

40 N

A man weighing 800N stands at rest on two bathroom scales so that his weight is distributed evenly over both scales. The reading on both scales is:

400N

A peice of rope is pulled by two people in a tug-of-war. Each pulls with 400 N of force. What is the tension in the rope?

400N

An object is pulled northward by a force of 10N and at the same time another force of 15 N pulls it southward. The magnitude of the resultant force on the object is

5 N

A stone is thrown horizontally from the top of a cliff. One second after it has left your hand, its vertical distance below the top of the cliff is

5 m

Which moves faster in m/s on a merry go round: a horse on the inside or a horse on the outside near the outer rail?

Outside horse

An archer shoots an arrow. Consider the action force to be the bowstring against the arrow. The reaction to this force is the

arrows push against the bowstring

When doing somersaults, you'll more easily rotate when your body is

balled up

Which would produce more force: driving into a very massive concrete wall with no "give", or having a head-on collision at the same speed with an identical car moving toward you with the same speed

both the same

Arnold Strongman and Suzie Small each pull very hard on opposite ends of a massless rope in a tug-of-war. The greater force on the rope is exerted by

both the same, interestingly enough

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

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

If a turntable's rotational speed is doubled, then the linear speed of a pet hamster sitting on the edge of the record will

double

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

Your pet hamster sits on a record player whose angular speed is constant. If he moves to a point twice as far from the center, then his linear speed

doubles

According to the impulse-momentum equation Ft = change in (mv), a person will suffer less injury falling on a wooden floor which "gives" than on a more rigid cement floor. The F in the above equation stands for the force exerted on the

either the force on the person or the force on the floor

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

ellipses

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 truck is moving at a constant velocity. Inside the storage compartment, a rock is dropped from the midpoint of the ceiling and strikes the floor below. The rock hits the floor:

exactly below the midpoint of the ceiling

The Newton is a unit of

force

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

It takes Pluto a longer time to orbit the sun than the Earth because Pluto

goes much slower, has further to go, CHOICES A AND B ARE CORRECT

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 needed to stop the truck is:

greater

If an object falling freely were somehow equipped with an odometer to measure the distance it travels, then the amount of distance it travels each succeeding second would be:

greater than the second before

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

greater the gravitational force between them

Consider a moon that orbits one of our most distant planets in an elliptical path. The distance that the moon covers each day is

greatest when the moon is closest to the planet

An object following a staright-line path at constant speed

has zero acceleration

A karate expert executes a swift blow and breaks a cement block with her bare hand. The magnitude of the force experienced by her hand is

identical to the force applied to the block

A woman carries a heavy box across a room at a constant speed. How much work does she do on the box while walking

none

A skydiver falls towards the Earth. The attraction of the Earth on the diver pulls the driver down. What is the reaction to this force?

none of these

communications and weather satelites always appear at the same place in the sky. This is because these satelites are

orbiting the Earth with a 24 hour period

A job is done slowly, while an identical job is done quickly. Both jobs require the same amount of work, but different amounts of

power

The period of a satelite, the time it takes for a complete revolution, depends on the satelite's

radial distance

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

remains unchanged

A rifle recoils while firing a bullet. The speed of the rifle's recoil is small because the

rifle has much more mass than the bullet

A projectile is fired vertically from the surface of Earth at 5 km/s. The projectile will

rise and fall back to Earth's surface

The force exerted on the tires of a car to directly accelerate it along a road is exerted by the

road

Acceleration due to gravity on the moon is less than on earth, and the moon is smaller than earth. So compared to an Earth satellite, a satellite in close orbit about the moon would travel

slower

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

Newton discovered

that gravity is universal

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

The force on an apple hitting the ground depends upon

the time of impact with the ground, the speed of the apple just before hits, whether or not the apple bounces, ALL OF THESE

The speeds of the planets about the sun depend on

their distances from the sun

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

twice as much

A 1000kg car and a 2000 kg car are hoisted the same distance. Raising the more massive car requires

twice as much work

If you push an object a given distance, while applying twice the force, you do

twice as much work

If you push an object twice as far while applying the same force, you do

twice as much work

Consider two planets in space that gravitationally attract each other. If the masses of both planets are doubled, and the distance between them is also doubled, then the force between them is

twice as much, half as much, four times as much, one quarter, NONE OF THESE

Put a pipe over the end of a wrench when trying to turn a stubborn nut on a bolt, to effectively make the wrench handle twice as long, you'll multiply the torque by

two

If you find that twice as much work is needed to perform a task but it takes twice as much time, the amount of power required is

unchanged

Whike an object near the Earth's surface is in free fall, its:

velocity increases