physical science exam

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

0 N.

What is the acceleration of a car that maintains a constant velocity of 100 km/h for 10 s?

0.

Two identical freight cars roll without friction towards each other on a level track. One rolls at 2 m/s and the other rolls at 1 m/s. After the cars collide, they couple and roll together with a speed o

0.5 m/s.

A 30 kg girl and 25 kg boy face each other on friction-free roller blades. The girl pushes the boy, who moves away at a speed of 1.0 m/s. The girl's speed is

0.83 m/s.

Consider massive gliders that slide friction-free along a horizontal air track. Glider A has a mass of 1 kg, a speed of 1 m/s, and collides with glider B, which has a mass of 5 kg and is at rest. If they stick upon collision, their speed after the collision will be

1/ 6 m/s

Two identical gliders slide toward each other on an air track. One moves at 1 m/s and the other at 2 m/s. They collide and stick. The combined mass moves at

1/2 m/s.

A 1 kg glider and a 2 kg glider both slide toward each other at 1 m/s on an air track. They collide and stick. The combined mass moves at

1/3 m/s

A 5 kg fish swimming at a speed of 1 m/s swallows an absent minded 1 kg fish swimming toward it at 4 m/s. The speed of the larger fish after lunch is

1/6 m/s.

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 gain in speed each second for a freely falling object is about

10 m/s.

A bag of groceries has a mass of 10 kg and a weight of about

100 N.

Ten seconds after starting from rest, a freely falling object will have a speed of about

100 m/s.

A tow truck exerts a force of 3000 N on a car, accelerating it at 2 m/s/s. What is the mass of the car?

1500 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 toy cart moves with a kinetic energy of 40 J. If it moves with twice the speed, its kinetic energy will be

160 J

A car moving at 50 km/h skids 20 m with locked brakes. How far will the car skid with locked brakes if it is traveling at 150 km/h?

180 m.

Exert 1 N for a distance of 1 m in 1 s and you deliver a power of

1W

Exert 100 J in 50 s and your power output is

2 W

A 1000 kg car moving at 10 m/s brakes to a stop in 5 s. The average braking force is

2000 N

You have kinetic energy when you run. If you run five times as fast, you'll have a kinetic energy

25 times as much.

How much power is expended if you lift a 100N rock 5 meters in 2 seconds?

250 W.

375 cm equals ______m.

3.75

The speed of light is approximately 3 X 108 m/s. How would this be written in conventional notation?

300 000 000 m/s

A 300 kg bear grasping a vertical tree slides down at a constant velocity. The friction force between the tree and the bear is

3000 N.

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

3000 N.

n the surface of Jupiter, where the acceleration due to gravity is about three times that of Earth, a 100 kg rock would have a weight of about

3000 N.

n scientific notation, the number 46,500,000 would be written

4.65 X 107

A bow is drawn so that it has 40J of potential energy. When fired, the arrow will ideally have a kinetic energy of

40 J.

A 20 N force and a 15 N force act on an object in opposite directions. What is the net force on the object?

5 N

A 5 kg fish swimming at a speed of 1 m/s swallows an absent minded 1 kg fish at rest. The speed of the larger fish after lunch is

5/6 m/s.

If a 150 pound person stands on a pair of bathroom scales, and leans so one of the scales reads 100 pounds, then the other scale reads

50 pounds.

The average momentum of a 70 kg runner who covers 400 m is 50 s is

560 kg⋅m/s.

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

6 N.

If a car increases its velocity from zero to 60 km/h in 10 s, its acceleration is

6 km/h/s.

A 5000 kg freight car runs into a 10,000 kg freight car at rest. They couple upon collision and move with a speed of 2 m/s. What was the initial speed of the 5000 kg car?

6 m/s.

What is 78,900,000,000 expressed in scientific notation?

78.9 X 109

A boxer punches a sheet of paper in midair and brings it from rest up to a speed of 40 m/s in 0.05 s. If the mass of the paper is 0.01kg, the force of the impact on the paper is about

8.0 N.

A 2 kg mass is held 4m above the ground. What is the approximate gravitational potential energy of the mass with respect to the ground?(Use 10 for gravity

80 J.

A sandbag is motionless in outer space. A second sandbag with 3 times the mass moving at 12 m/s collides with it and they both stick together, and move at a speed of

9 m/s

You have kinetic energy when you run. If you run three times as fast, you'll have a kinetic energy

9 times as much.

Which requires more work: lifting a 50 kg sack vertically 2 m or lifting a 25 kg sack vertically 4 m?

Both require the same amount of work.

Bronco the skydiver falls toward Earth. The attraction of the Earth on Bronco pulls him down. The reaction to this force is

Bronco pulling up on the Earth.

If you push as object with twice the work input for twice the time, your power is

The same amount as for half the work in half the time.

A 50 kg sack is lifted vertically 2 m in the same time as a 25 kg sack is lifted vertically 4 m. The power expended in raising the 50 kg sack compared to the power used to lift the 25 kg sack is

The same.

An object is raised above the ground gaining a certain amount of potential energy. If the same object is raised twice as high, it gains

Twice as much potential energy

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

Twice as much work.

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

Twice as much work.

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

Twice as much work.

If you do work on an object in half the time, your power output is

Twice the usual power output.

Consider an object in free fall. Each second the object falls what happens to the distance

a greater distance than in the second before.

A scientific theory is

a synthesis of collection of data that includes well-tested guesses.

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

acceleration

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

add to equal your weight.

Science, art, and religion do not contradict one another because

all three have different domains.

A scientific hypothesis is

an educated guess that has yet to be proven by experiment.

The feature that makes a hypothesis scientific is that there be

an experiment that can confirm or refute it.

length, mass, time, and temperature are the four of seven SI

base units

Which has more potential energy, a 50kg load 2 meters high, or a 100kg load 1 meter high?

both the same.

Which one of these statements is a scientific hypothesis? a.) Michael Jordan is the greatest basketball player of all time. b.) An undetectable energy source is at the center of the Earth. c.) The back side of the moon has cities about the size of Chicago. d.) The universe is surrounded by a second universe, which cannot be detected.

c.) The back side of the moon has cities about the size of Chicago.

The law of inertia applies to a.) objects at rest. b.) moving objects. c.) both of these.

c.) both of these.

Combinations of the SI base units, which are used to measure quantities such as volume, speed, and pressure are called

derived units

The two measurements necessary for calculating average speed are

distance and time.

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

double.

If you push a crate across the floor with the force of 100 N and it slides at constant velocity, then the force of friction between the crate and the floor is

equal to 100 N.

In science, changing your mind when confronted with evidence that does not agree with your thinking is seen

essential to scientific progress.

A truck is moving at 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 where?

exactly below the midpoint of the ceiling.

a glass vase that falls on the floor will be less likely to break if the floor is carpeted. This is because the

force of the impact will be less because the time of impact will be longer.

A moving freight car collides with an identical car at rest on the track. The cars couple together. Compared with the speed of the first car before the collision, the speed of the combined cars after the collision is

hald as much

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

halves.

The difference between a hypothesis and a theory is that a hypothesis

is a guess that has not been well-tested, whereas a theory is a synthesis of well-tested and refined guesses.

The SI unit for measuring temperature is the

kelvin.

An object that has potential energy may have this energy because of its

location.

A kilogram is a measure of an object's

mass.

An object that has kinetic energy must have

momentum.

Kinetic energy is the energy an object has due to its

motion

An object that has kinetic energy must be

moving.

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

road

Whirl a rock at the end of a string and it follows a circular path. If the string breaks, the rock tends to follow a

straight line path.

Your weight is

the gravitational attraction between you and the Earth.

A light woman and a heavy man jump from an airplane 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. This best demonstrates that

the milk carton has inertia.

An object weighs 30 N on Earth. A second object weighs 30 N on the Moon. Which has the greater mass?

the one on the Moon.

A moving freight car collides with an identical car at rest on the track. The collision is elastic. Compared with the speed of the first car before the collision, the speed of the second of the car after the collision is

the same

A tennis ball is launched from a launching machine. Compared with the amount of impulse on each ball, the amount of impulse on the machine is

the same.

Compared with the mass of a certain object on Earth, the mass of the same object on the Moon is

the same.

Galileo found that a ball rolling down one inclined plane rolls how far up another inclined plane?

to nearly the same height as it initially started.

The minimum number of forces that makes up an interaction is

two.

Any factor in an experiment that can change is referred to as a

variable

Your backpack falls from your seat onto the floor of a bus that is moving at a constant speed of 20 km/h. During its fall, its horizontal speed, relative to the road is

zero

The force required to maintain an object at a constant velocity in free space is equal to

zero.

When Nellie Newton pushes an object with twice the force for twice the distance, then the work she does on the object is

Four times as much.

If you push for an hour against a stationary wall, you do no work

On the wall.