Science101Exam1notes

A 10-kg block is pushed across a horizontal surface with a horizontal force of 20 N against a friction force of 20 N. The acceleration of the block is ______m/s2.

0.0 (with margin: 0.0)

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

0.5 m/s.

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

1 W.

If a projectile is fired straight up at a speed of 10 m/s, neglecting air resistance, the time it takes to reach the top of its path is

1 s.

If your mass remained the same while the mass of Earth doubled while staying the same size, your mass would change by a factor of ______.

1.0 (with margin: 0.0)

What is the buoyant force acting on a 10-ton ship floating in a fresh-water lake?

10 tons

A machine puts out 100 W of power for every 1000 W put into it. The efficiency of the machine is

10%

A machine puts out 100 W of power for every 1000 W put into it. The efficiency of the machine is

10%.

A gun with a muzzle velocity of 100 m/s is fired horizontally from a tower. Neglecting air resistance, how far downrange will the bullet be 1 s later?

100 m

Escape speed from Earth is

11.2 km/s.

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

16 times the kinetic energy.

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%.

Exert 100 J in 50 s and your power output is

2 W.

A 50-kg sack is lifted 2 m in the same time as a 25-kg sack is lifted 2 m. The power expended in raising the 50-kg sack is ____ times the power used to lift the 25-kg sack.

2.0 (with margin: 0.0)

A rock suspended by a weighing scale weighs 3 N when submerged in water and 5 N out of water. What is the density of the rock in g/cm3?

2.5 (with margin: 0.1) 0.0 (with margin: 0.0)

A rock suspended by a weighing scale weighs 14 N out of water and 11 N when submerged in water. What is the buoyant force on the rock?

3 N.

A 5000-kg freight car crashes 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 freight car?

4 m/s

If a ball rolls down an inclined plane and picks up 4 m/s each second it rolls, its acceleration is

4 m/s2.

The average speed of a deer traveling a distance of 2 km in a time of one-half hour is _______km/hr.

4.0 (with margin: 0.0)

A 1-kg mass that weighs 10 N has 40 J of potential energy relative to the ground. What is its height in meters?

4.0 (with margin: 0.1)

A stone is thrown horizontally from the top of a cliff. One second after leaving your hand it drops a vertical distance of

5 m.

Nellie runs the length of a 100-yard football field in a time of 20 seconds. Her average running speed is Correct!

5 yards/s.

Without air resistance, a ball tossed at an angle of 40o with the horizontal goes as far downrange as one tossed at the same speed at an angle of

50 degrees

In raising a 5000-N piano with a pulley system, for every 1 m of rope pulled down, the piano rises 0.1 m. Ideally, this means the force needed to lift the piano is

500 N.

A diver who weighs 500 N steps off a diving board 10 m above the water hits the water with kinetic energy of

5000 J.

The height of a 1.6 meter tall structure was measured to be 1.5 meters. The percent error is

6%

A projectile is launched at an angle of 15° above the horizontal and lands downrange. With no air resistance, what other projection angle for the same speed would produce the same downrange distance?

75°

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

8.0 (with margin: 0.0)

The flight of a blimp best illustrates Correct!

Archimedes' principle.

The ultimate source of energy from fossil fuels is the

Sun.

Compared to a bar of pure gold, the density of a pure gold ring is

The same

I have answered all questions on the scantron, indicated my version (A, B, C, D, or E) of my exam on the scantron, filled in my last and first name, and double checked my 9 digit student ID with my ID card. I went over the scantron sheet to make absolutely sure that there are no blanks. My worksheet has my name and 9 digit student ID on it

Yes, I did all of those things

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

a straight-line path.

Without air resistance, a projectile fired horizontally at 8 km/s from a mountaintop will

all the above.

The Moon falls toward Earth in the sense that it falls

beneath the straight-line path it would follow without gravity

A fish normally displaces its own

both

A rock is thrown upward at 50° with respect to the horizontal. As it rises in free fall, its vertical component of velocity

decreases.

The pressure in a liquid depends on liquid

density and depth

If a loaf of bread is compressed, its

density increases.

A given net force propels an object along a straight-line path. If the net force were doubled, its acceleration would

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

A simple machine CANNOT multiply

energy.

The reason a 10-kg rock falls no faster than a 5-kg rock in free fall is that the

force/mass ratio is the same for both.

Science and technology are

fundamentally different from each other.

Lifting a 100-N load with 50 N of force lifts it

half as high.

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

increases.

When dishes remain on a table when you yank the tablecloth beneath them, you're demonstrating

inertia.

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

is zero.

In a vacuum, a marshmallow becomes

larger

If air speed is greater along the top surface of a bird's wings, pressure of the moving air there is

less.

If the running speed of Fast Freda doubles, what also doubles is her

momentum

A heavy truck and a small truck roll down a hill. Neglecting friction, at the bottom of the hill the heavy truck has greater

momentum.

A freely falling object has a downward speed of 40 m/s at one instant. Exactly 1 s later its speed will be

more than 45 m/s.

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

none of the above

A scientific hypothesis can be disproved with

one reproducible experiment.

Tangential velocity is velocity

parallel to the surface of the Earth.

Of the sciences known as physics, chemistry, and biology, the most basic is

physics

When you stand on tiptoes on a bathroom scale, there is an increase in

pressure on the scale, not registered as weight.

Buoyant force acts upward on a submerged object because

pressure up on bottom is greater than downward pressure on top of the object.

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

pull of the ball's mass on Earth.

Suppose a gun were made of strong lightweight material with a pellet that is more massive than the gun. Then firing speed is greater for the

recoiling gun.

A rock is thrown upward at 50° with respect to the horizontal. As it rises in free fall, its horizontal component of velocity

remains unchanged.

A Mack truck and a Mini Cooper traveling at the same speed collide head-on. The collision force is greatest on the

same

A moving object has

speed, velocity, momentum, energy

Compared to the density of water, the density of a fish is

the same.

When you push an object a certain distance while applying twice the force, you do

twice as much work.

A rising balloon is buoyed up with a force equal to the

weight of air it displaces.

Atmospheric pressure is caused by the

weight of the atmosphere.

Strictly speaking, when you step off a curb you are momentarily

weightless.

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

zero.