SCEN101 Exam 1

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

4 km/hr

If a ball rolls down an inclined plane and picks up 4 m/s each second it rolls, its acceleration is 10 m/s2. one half of 4 m/s. one half of 4 m/s2. 4 m/s2.

4 m/s2

When you stand on tiptoes on a bathroom scale, there is an increase in weight reading. pressure on the scale, not registered as weight. both weight and pressure on the scale. none of the above

pressure on the scale, not registered as weight.

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

increases

When dishes remain on a table when you yank the tablecloth beneath them, you're demonstrating constant motion. ΣF = 0. friction. inertia.

inertia

Whenever the net force on an object is zero, its acceleration and velocity are the same. may be zero. is zero. none of the above

is zero

In a vacuum, a marshmallow becomes does not change. smaller. larger.

larger

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.

m1*v1 + m2*v2 = (m1 +m2) * vf 1kg * 0m/s + 2kg * 12m/s = (1+2kg)*vf 24 kg * m/s = 3kg * vf Vf = 8 m/s

If the running speed of Fast Freda doubles, what also doubles is her momentum. kinetic energy. both of these. neither of these.

momentum

A freely falling object has a downward speed of 40 m/s at one instant. Exactly 1 s later its speed will be the same. 45 m/s. more than 45 m/s. 60 m/s.

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 twice as much. half as much. four times as much. one-quarter. none of the above

none of the above

A scientific hypothesis can be disproved with one reproducible experiment. many tests by many scientists. disapproval of other scientists. philosophical reasoning.

one reproducible experiment.

Of the sciences known as physics, chemistry, and biology, the most basic is chemistry. biology. physics. none in particular

physics

The flight of a blimp best illustrates Archimedes' principle. Pascal's principle. Bernoulli's principle. Boyle's law.

Archimedes' principle.

A moving object has speed. momentum. energy. velocity. all of the above

all of the above

Without air resistance, a projectile fired horizontally at 8 km/s from a mountaintop will return to its starting position and repeat its falling behavior. trace a curve that matches Earth's curvature. accelerate downward at g as it moves horizontally. all the above. none of the above.

all of the above

The Moon falls toward Earth in the sense that it falls with an acceleration of 10 m/s2, as do apples on Earth. beneath the straight-line path it would follow without gravity both of these neither of these

beneath the straight-line path it would follow without gravity

A fish normally displaces its own volume of water. weight of water. both neither

both

The pressure in a liquid depends on liquid depth. density. both neither

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. remains unchanged. increases.

decreases

If a loaf of bread is compressed, its molecules decrease in size. density decreases. density increases. none of the above

density increases.

A given net force propels an object along a straight-line path. If the net force were doubled, its acceleration would be half. quadruple. double. stay the same. none of the above

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 quadrupled. zero. doubled. unchanged.

doubled

A simple machine CANNOT multiply force. energy. distance. none of the above

energy

The reason a 10-kg rock falls no faster than a 5-kg rock in free fall is that the 10-kg rock has greater acceleration. 5-kg rock has greater acceleration. force of gravity is the same for both. force/mass ratio is the same for both.

force/mass ratio is the same for both.

Compared to the density of water, the density of a fish is the same. more. less.

the same

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 times

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. 14 N. 25 N. 11 N.

3 N

A car moves 4 times as fast as another identical car. Compared with the slower car, the faster car has 12 times the KE 16 times the KE 4 times the KE 8 times the KE

16 times the KE

If a power plant is 30% efficient, and the transmission system that delivers power to consumers is 60% efficient, then the overall efficiency is 60%. 18%. 90%. 30%. none of the above

18%

Exert 100 J in 50 s and your power output is 4 W. 2 W. 1/2 W. 1/4 W.

2 W

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

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 1.5 m/s. 1.0 m/s. 0.67 m/s. 0.5 m/s.

0.5 m/s

Exert 1 N for a distance of 1 m in 1 s and you deliver a power of 1/3 W. 2 W. 1 W. 3 W. none of the above

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 2 s. 10 s. 1 s. not enough information

1 s

What is the buoyant force acting on a 10-ton ship floating in a fresh-water lake? 10 tons more than 10 tons less than 10 tons not enough information

10 tons

A machine puts out 100 W of power for every 1000 W put into it. The efficiency of the machine is 50%. 90%. 10%. 110%.

10%

A machine puts out 100 W of power for every 1000 W put into it. The efficiency of the machine is 90%. 10%. 110%. 50%. none of the above

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? 500 m 50 m 100 m 98 m none of the above

100 m

Escape speed from Earth is 42.2 km/s. 9.8 km/s. 11.2 km/s. 8 km/s.

11.2 km/s

A stone is thrown horizontally from the top of a cliff. One second after leaving your hand it drops a vertical distance of 10 m. 15 m. 5 m.

5 m.

Nellie runs the length of a 100-yard football field in a time of 20 seconds. Her average running speed is 5 yards/s. 1/2 yard/s. 50 yards/s. not enough information

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 45o 50o 60o none of these

50

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. 5000 N. 50 N. not enough information

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 510 J. more than 5000 J. 500 J. 5000 J. 10 J.

5000 J.

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 8 m/s 6 m/s 5 m/s none of the above

6 m/s

The height of a 1.6 meter tall structure was measured to be 1.5 meters. The percent error is 0.6% 0.06% 6%

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? 90° 75° 45° 50° 30°

75°

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 ______.

??

Compared to a bar of pure gold, the density of a pure gold ring is more. less. the same.

The same

If gravity between the Sun and Earth suddenly vanished, Earth would continue moving in an inward spiral path. a curved path. a straight-line path. an outward spiral path.

a straight-line

Buoyant force acts upward on a submerged object because it acts in a direction to oppose gravity. if it acted downward, nothing would float. the weight of fluid displaced reacts with an upward force. pressure up on bottom is greater than downward pressure on top of the object.

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. air resistance acting against the ball. acceleration of the ball. nonexistent. none of the above

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 pellet. recoiling gun. both are the same none of the above

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. increases. decreases.

remains unchanged.

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

same

The ultimate source of energy from fossil fuels is the Sun. photosynthesis process. natural processes in Earth's interior. radioactivity in Earth's interior.

sun

When you push an object a certain distance while applying twice the force, you do the same amount of work. twice as much work. four times as much work.

twice as much work.

A rising balloon is buoyed up with a force equal to the density of surrounding air. weight of the balloon and its contents. weight of air it displaces. atmospheric pressure

weight of air it displaces.

Atmospheric pressure is caused by the weight of the atmosphere. temperature of the atmosphere. effect of the Sun's energy on the atmosphere. density of the atmosphere.

weight of the atmosphere.

Science and technology are fundamentally different from each other. responsible for all the good in the world. responsible for all that is wrong in the world. really one and the same.

fundamentally different from each other.

Lifting a 100-N load with 50 N of force lifts it twice as high half as high. as high.

half as high

If air speed is greater along the top surface of a bird's wings, pressure of the moving air there is unaffected. less. more. turbulent.

less

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. speed. acceleration. all of the above none of the above

momentum

Tangential velocity is velocity perpendicular to the surface of the Earth. attributed to satellites moving in any direction. parallel to the surface of the Earth.

parallel to the surface of the Earth.

Strictly speaking, when you step off a curb you are momentarily in space. in orbit. weightless.

weightless

The force required to maintain an object at a constant velocity in free space is equal to the weight of the object. the force required to stop it. zero. the mass of the object.

zero