Physics Final Exam

A parachutist steps from a hovering helicopter and falls for 5 s before reaching terminal velocity. During this 5-s interval, her acceleration

decreases

When a simple machine multiplies force, it decreases

distance moved

As drops fall from a leaky faucet they become

farther apart as they fall

Arnold Strongman wearing socks and Suzie Small in gym shoes have a tug-of-war on a polished floor. The likely winner is

Suzie

Phil Physiker standing at the edge of a cliff throws one ball straight up and another ball straight down, both with the same speed. Both balls hit the ground at

The same speed in different times

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

the person's body pulling on Earth

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

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

To catch a fast-moving softball with your bare hand, you extend your hand forward just before the catch and then let the ball ride backward with your hand. Doing this reduces the catching force because the

time of catch is increased

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

8.0 N

If you jump vertically while inside a fast-moving train that is slowing down, you land

A bit ahead of your original position

To a scientist a "fact" is

A phenomenon about which competent observers, who have made a series of observations or measurements, are in agreement.

If gravity between the Sun and Earth suddenly vanished, Earth would move in

A straight-line path

A 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 rock thrown straight up reaches the exact top of its path, its velocity is

zero and its acceleration is 10 m/s^2

A 10N falling object encounters 10N of air resistance. The net force on it is

0 N

A mosquito flying at 3 m/s encounters a 3-m/s breeze blowing in the same direction, which gives it a resulting speed over the ground of

0 m/s

A 2-kg rifle is horizontally suspended by a pair of strings so that recoil can be measured. The rifle fires a 0.001-kg bullet at a speed of 200 m/s. The recoil velocity of the rifle is about

0.1 m/s

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

1 kg * m/s

If you toss a ball straight upward at 40 m/s with no air resistance, one second before it reaches the top of its path its speed is

10 m/s

From the edge of a roof you throw a snowball downward that strikes the ground with 100 J of kinetic energy. Then you throw a second snowball upward with the same initial speed, and this too falls to the ground. Neglecting air resistance, the second snowball hits the ground with a kinetic energy of

100 J

Consider a monkey wrench released at rest at the far edge of the solar system that drops to Earth by virtue of only Earth's gravity. The wrench will strike Earth's surface with a speed of about

11 km/s

What is the mass of a ball moving at 4 m/s with a momentum of 48 kg * m/s

12 kg

If a power plant is 30% efficient, and the transmission system that delivers power to consumers is 60% efficient, then the overall efficiency is

18%

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

180 m

A 2-kg mass that weighs 20 N has 40 J of potential energy relative to the ground. What is its height?

2 m

A 10-kg block is pushed across a horizontal surface with a horizontal force of 30 N against a friction force of 10 N. The acceleration of the block is

2 m/s^2

If there were no gravity, a ball thrown upward at an angle would follow a straight line path. Due to gravity, however, at the end of 2 s it is

20 m below the straight line

What applied horizontal force will accelerate a 400kg crate at 1m/s^2 across a factory floor against a friction force half its weight

2000 N

While in an airplane flying at 100 km/h you look down from the window and spot another airplane flying at the same speed in the opposite direction. Relative to you, the speed of the spotted plane is

200km/h

The average speed of a horse that gallops 10 kilometers in 30 minutes is

20km/h

a 2500 N pile driver ram falls 10 m and drives a post 0.1 m into the ground. The average impact force on the ram is

250,000

An 800-N woman stands at rest on two bathroom scales so that one scale shows a reading of 500 N. The reading on the other scale is

300N

Two people, one twice as massive as the other, attempt a tug-of-war with 12 m of rope on frictionless ice. After a brief time, they meet. The heavier person slides a distance of

4 m

Suppose a miracle car has a 100% efficient engine and burns fuel having an energy content of 40 MJ/L energy content. If the air drag and overall frictional forces on this car traveling at highway speeds is 1000 N, what is the overall limit in distance per liter it could be driven on the highway?

40 km

When you step off a bus moving at 2m/s, your horizontal speed when you meet the ground is

About 2m/s

Which has zero acceleration?

All of the above

When you simultaneously drop a light tennis ball and a heavy bowling ball, they hit the floor

At the same speed

The International Space Station orbits at an average 360 km altitude so that it is mainly above

Atmosphere

An airplane flies at 40 m/s at an altitude of 50 meters. The pilot drops a heavy package which falls to the ground below. Neglecting air resistance, the package will land

Beneath the plane

Which of these collisions is more damaging; driving into a concrete wall with no "give", or colliding head on with an identical car moving toward you at the same speed?

Both the same

A bucket of cement is raised by a rope at constant speed at a construction site. The upward force on the bucket supplied by the rope is

Equal

In contrast to Aristotles way of explaining nature, Galileo relies on

Experiment

In answer to the question, "When a plant grows, where does the material come from?" the ancient Greek philosopher Aristotle hypothesized by logic that all material came from the soil. Which of the following experimental tests might best prove Aristotle's hypothesis to be correct or incorrect?

Grow the trees in a pot and measure the mass of the soil before and after the tree grows to a certain height

A block is pulled across a floor as shown below in the vector diagram. The force vector F has the greatest component in the... And the component is...

Horizontal direction Smaller than the vector F

A bullet is fired from a gun. The speed of the bullet will be about the same as the speed of the recoiling gun

If the mass of the bullet equals the mass of the gun

Once a basketball player's feet are off the floor in making a jump, the jumper's acceleration

Is g; no more; no less

According to Aristotle, a rolled ball eventually comes to a stop because

It seeks its natural state of rest

A melon is projected into the air with 100 J of kinetic energy in the presence of air resistance. When it returns to its initial level its kinetic energy is

Less than 100 J

A kilogram is a unit of

Mass

Each of us weighs a slightly less inside the ground floor of a skyscraper than we do on the ground away from the skyscraper because the

Mass of the building attracts us upward slightly

Why doesn't the Moon fall toward Earth like apples do?

Moon does fall but due to its tangential motion it falls around Earth

When a rocket ship gaining speed in remote, gravity-free outer space runs out of fuel, it

No longer gains speed

An object is pulled with three forces: one at 20N to the right, another at 40N to the right, and the third at 30N to the left. The net force is

None of the above

The power expended for a barbell raised 2.0 m in 2 s is

Not enough information

According to Galileo, a rolled ball eventually comes to a stop because

Of friction

A baseball weighs 1.5N on Earth. Another type of ball weighs 1.5N on the Moon. The ball with the greater mass is the

Other type of ball

The force of gravity on a satellite in circular orbit doesn't change its speed because the force is

Perpendicular to its direction of motion

What statement most accurately describes what scientists do?

Scientists falsify hypotheses

An empty jug of weight W is at rest on a table. When water of weight w is poured into it, the amount of support force supplied by the table is

W + w

A crate is at rest on a horizontal floor, with nobody pushing. The friction force acting on the crate is

Zero

In science, a theory is

a synthesis of a large body of well-tested knowledge

You can experience weight

all of the above

You experience weightlessness

all of the above

A math book and a science 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

g/2

The Sun is spherical due to

gravitation

The force of a boxer's punch is greater when it hits a

heavy punching bag

Perturbations of planets are due to

interplanetary forces

The Early Bird communication satellite hovers over the same point on Earth's equator indefinitely because

its orbital period is 24 hours

An object may have potential energy because of its

location

In science, facts

may change

A fan attached to an ice sailcraft stalled on a windless day blows air into the sail that bounces backward upon impact. The boat

moves in the direction of the wind impact force

A satellite in an elliptical orbit travels at constant

none of the above

A scientific hypothesis can be disproved with

one reproducible experiment

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

same for both