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A 1000 kg sportscar accelerates from zero to 25 m/s in 7.5 s. What is the average power delivered by the automobile engi

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A 1000 kg sportscar accelerates from zero to 25 m/s in 7.5 s. What is the average power delivered by the automobile engine?

- 20.8 kW
- 30.3 kW
- 41.7 kW
- 52.4 kW

A bobsled makes a run down an ice track starting at 150 m vertical distance up the hill. If there is no friction, what is the velocity at the bottom of the hill?

- 27 m/s
- 36 m/s
- 45 m/s
- 54 m/s

A jet engine develops 105 N of thrust in moving an airplane forward at a speed of 900 km/hr. What is the power developed by the engine?

- 500 kW
- 1 MW
- 2.5 MW
- 5 MW

A speedboat requires 80 kW to move at a constant speed of 15 m/s. What is the resistive force of the water at this speed?

- 2667 N
- 5333 N
- 6500 N
- 7711 N

A pole vaulter clears 6 m. With what velocity does he strike the mat in the landing area?

- 2.7 m/s
- 5.4 m/s
- 10.8 m/s
- 21.6 m/s

A parachutist of mass 50 kg jumps out of an airplane at a height of 1000 m. The parachute deploys, and she lands on the ground with a velocity of 5 m/s. How much energy was lost to air friction during this jump?

- 49,375 J
- 98,750 J
- 197,500 J
- 489,375 J

Water flows over a section of Niagara Falls at a rate of 1.2 x 106 kg/s and falls 50 m. What is the power wasted by the waterfall?

- 588 MW
- 294 MW
- 147 MW
- 60 MW

A baseball outfielder throws a baseball of mass 0.15 kg at a speed of 40 m/s and initial angle of 30° . What is the kinetic energy of the baseball at the highest point of the trajectory? Ignore air friction.

- zero
- 30 J
- 90 J
- 120 J

A Russian weightlifter is able to lift 250 kg 2 m in 2 s. What is his power output?

- 500 W
- 2.45 kW
- 4.9 kW
- 9.8 kW

A worker pushes a 500 N weight wheelbarrow up a ramp 50.0 m in length and inclined at 20° with the horizontal. What potential energy change does the wheelbarrow experience?

- 1500 J
- 3550 J
- 4275 J
- 8550 J

A worker pushes a 500 N weight wheelbarrow to the top of a 50.0 m ramp, inclined at 20° with the horizontal, and leaves it unattended. The wheelbarrow is accidentally bumped causing it to slide back down the ramp during which a 80 N frictional force acts on it over the 50.0 m. What is the wheelbarrow's kinetic energy at the bottom of the ramp? (g = 9.8 m/s2 )

- 4550 J
- 6550 J
- 8150 J
- 13100 J

What is the kinetic energy of a 0.135 kg baseball thrown at 40 m/s (90 mph)?

- 54 J
- 87 J
- 108 J
- 216 J

A 15.0 kg crate, initially at rest, slides down a ramp 2.0 m long and inclined at an angle of 20° with the horizontal. If there is no friction between ramp surface and crate, what is the kinetic energy of the crate at the bottom of the ramp? (g = 9.8 m/s2 )

- 221 J
- 688 J
- 10.2 J
- 100 J

A worker pushes a wheelbarrow with a force of 50 N over a level distance of 5 m. If a frictional force of 43 N acts on the wheelbarrow in a direction opposite to that of the worker, what net work is done on the wheelbarrow?

- 250 J
- 215 J
- 35 J
- 10 J

If during a given physical process the only force acting on an object is friction, which of the following must be assumed in regard to the object's kinetic energy?

- decreases
- increases
- remains constant
- cannot tell from the information given

As an object is lowered into a deep hole in the surface of the earth, which of the following must be assumed in regard to its potential energy?

- increase
- decrease
- remain constant
- cannot tell from the information given

When an object is dropped from a tower, what is the effect of the air resistance as it falls?

- does positive work
- increases the object's kinetic energy
- increases the object's potential energy
- None of these choices are valid.

The unit of work, joule, is dimensionally the same as which of the following?

- newton/second
- newton/kilogram
- newton-second
- newton-meter

The unit of power, watt, is dimensionally the same as which of the following?

- joule-second
- joule/second
- joule-meter
- joule/meter

The rate at which work is done is equivalent to which of the following?

- increase in potential energy
- thermal energy
- potential energy
- power

A worker pushes a wheelbarrow with a horizontal force of 50 N over a distance of 5 m. What work does the man do?

- 10 J
- 1250 J
- 250 J
- 55 J

A 40 N crate is pulled up a 5 m inclined plane at a constant velocity. If the plane is inclined at an angle of 37° to the horizontal and there exists a constant force of friction of 10 N between the crate and the surface, what is the net gain in potential energy by the crate in the process?

- 120 J
- -120 J
- 200 J
- -200 J

A 40 N crate starting at rest slides down a rough 6 m long ramp, inclined at 30° with the horizontal. The force of friction between crate and ramp is 6 N. What will be the velocity of the crate at the bottom of the incline?

- 1.6 m/s
- 3.3 m/s
- 4.5 m/s
- 6.4 m/s

Which of the following is an example of a non-conservative force?

- gravity
- magnetism
- Both magnetism and gravity
- friction

Which of the following is that form of energy associated with an object's motion?

- potential
- thermal
- bio-chemical
- kinetic

Which of the following is that form of energy associated with an object's location in a conservative force field?

- potential
- thermal
- bio-chemical
- kinetic

A 50 N crate is pulled up a 5 m inclined plane by a worker at constant velocity. If the plane is inclined at an angle of 37° to the horizontal and there exists a constant force of 10 N between the crate and the surface, what is the force applied by the worker?

- zero
- 20 N
- 30 N
- 40 N

A small wagon moving at constant velocity carries a 200 N crate 10 m across a level surface. What is the net work done in the process?

- zero
- 1/20 J
- 20 J
- 2000 J

The quantity of work equal to one joule is also equivalent to which of the following?

- watt
- watt/s
- watt x s
- watt/s2

A 3 kg object starting at rest falls to the ground from a height of 10 m. Just before hitting the earth what will be its kinetic energy? (g = 9.8 m/s2 and assume air resistance is negligible.)

- 98 J
- 0.98 J
- 29.4 J
- 294 J

An arrow, shot straight up from a crossbow has an initial velocity of 50 m/s. Ignore energy lost to air friction. How high will the arrow rise?

- 49 m
- 62.4 m
- 98 m
- 127.5 m

What is the minimum amount of energy required for an 80-kg climber carrying a 20-kg pack to climb Mt. Everest, 8850 m high?

- 8.67 mJ
- 4.16 mJ
- 2.47 mJ
- 1.00 mJ

A professional skier reaches a speed of 56 m/s on a 30° ski slope. Ignoring friction, what is the minimum distance along the slope the skier would have to travel, starting from rest?

- 110 m
- 160 m
- 320 m
- 640 m

A girl and her bicycle have a total mass of 40 kg. At the top of the hill her speed is 5 m/s. The hill is 10 m high and 100 m long. If the force of friction as she rides down the hill is 20 N, what is her speed at the bottom?

- 5 m/s
- 10 m/s
- 11 m/s
- She stops before she reaches the bottom.

Old Faithful geyser in Yellowstone Park shoots water more or less hourly to a height of 40 meters. With what velocity does the water leave the ground?

- 7.0 m/s
- 14.0 m/s
- 19.8 m/s
- 28.0 m/s

An 80,000 kg airliner is flying at 900 kilometers/hour at a height of 10 kilometers. What is its total energy (kinetic + potential)?

- 250 MJ
- 478 MJ
- 773 MJ
- 10,340 MJ

A 1200 kg automobile moving at 25 m/s has the brakes applied with a deceleration of 8 m/s2 . How far does the car travel before it stops?

- 39 m
- 47 m
- 55 m
- 63 m

A girl and her bicycle have a total mass of 40 kg. At the top of the hill her speed is 5 m/s and her speed doubles as she rides down the hill. The hill is 10 m high and 100 m long. How much kinetic energy and potential energy is lost to friction?

- 2420 J
- 1500 J
- 2000 J
- 3920 J

A 60 g golf ball is dropped from a height of 2 m and rebounds to 1.5 m. How much energy is lost?

- 0.29 J
- 0.5 J
- 0.88 J
- 1 J

A golf ball hits a wall and bounces back at 3/4 the original speed. What part of the original kinetic energy of the ball did it lose in the collision?

- 1/4
- 3/8
- 7/16
- It did not lose kinetic energy.

If both the mass and the velocity of a ball are tripled, the kinetic energy is increased by a factor of

- 3
- 6
- 9
- 27

A 2 kg ball which originally has zero kinetic and potential energy is dropped into a well which is 10 m deep. Just before the ball hits the bottom, the sum of its kinetic and potential energy is

- 0
- 196 J
- -196 J
- 392 J

A 2 kg ball which originally has zero potential and kinetic energy is dropped into a well which is 10 m deep. After the ball comes to a stop in the mud, the sum of its potential and kinetic energy is

- 0
- 196 J
- -196 J
- 392 J

A hill is 100 m long and makes an angle of 12° with the horizontal. As a 50 kg jogger runs up the hill, how much work does gravity do on the jogger?

- 49,000 J
- 10,000 J
- -10,000 J
- zero

Two blocks are released from the top of a building. One falls straight down while the other slides down a smooth ramp. If all friction is ignored, which one is moving faster when it reaches the bottom?

- The block that went straight down.
- The block that went down the ramp.
- They both will have the same speed.
- Insufficient information to work the problem.

A simple pendulum, 2.0 m in length, is released by a push when the support string is at an angle of 25° from the vertical. If the initial speed of the suspended mass is 1.2 m/s when at the release point, to what maximum angle will it move in the second half of its swing? (g = 9.8 m/s2 )

- 37°
- 30°
- 27°
- 21°

An automobile delivers 30 hp to its wheels when moving at a constant speed of 22 m/s. What is the resistance force on the automobile at this speed? (1 hp = 746 watts)

- 18,600 N
- 410,000 N
- 1,020 N
- 848 N

I use a rope to swing a 10 kg weight around my head. The rope is 2 m long and the tension in the rope is 20 N. In half a revolution how much work is done by the rope on the weight?

- 40 J
- 126 J
- 251 J
- 0

The work done by static friction is always

- positive
- negative
- along the surface
- zero

A simple pendulum, 2.0 m in length, is released with a push when the support string is at an angle of 25° from the vertical. If the initial speed of the suspended mass is 1.2 m/s when at the release point, what is its speed at the bottom of the swing? (g = 9.8 m/s2 )

- 2.3 m/s
- 2.6 m/s
- 2.0 m/s
- 0.5 m/s

A horizontal force of 200 N is applied to a 55 kg cart across a 10 m level surface. If the cart accelerates at 2.0 m/s2 then what force of friction acts to retard the motion of the cart?

- 110 N
- 90 N
- 80 N
- 70 N

A baseball catcher puts on an exhibition by catching a 0.15 kg ball dropped from a helicopter at a height of 101 m. What is the speed of the ball just before it hits the catcher's glove 1.0 m above the ground? (g = 9.8 m/s2 and ignore air resistance)

- 44.3 m/s
- 38.0 m/s
- 31.3 m/s
- 22.2 m/s

A baseball catcher puts on an exhibition by catching a 0.15 kg ball dropped from a helicopter at a height of 100 m above the catcher. If the catcher "gives" with the ball for a distance of 0.75 m while catching it, what average force is exerted on the mitt by the ball? (g = 9.8 m/s2 )

- 78 N
- 119 N
- 196 N
- 392 N

A horizontal force of 200 N is applied to move a 55 kg cart across a 10 m level surface. What work is done by the 200 N force?

- 4000 J
- 5400 J
- 2000 J
- 2700 J

A simple pendulum, 1.0 m in length, is released from rest when the support string is at an angle of 35° from the vertical. What is the speed of the suspended mass at the bottom of the swing? (ignore air resistance, g = 9.8 m/s2 )

- 0.67 m/s
- 0.94 m/s
- 1.33 m/s
- 1.88 m/s

A pile driver drives a post into the ground. The mass of the pile driver is 2500 kg and it is dropped through a height of 8 m on each stroke. If the resisting force of the ground is 4 x 106 N, how far is the post driven in on each stroke?

- 4.9 cm
- 9.8 cm
- 16.0 cm
- 49.0 cm

A 2000-kg ore car rolls 50 meters down a frictionless 10° incline. If there is a horizontal spring at the end of the incline, what spring constant is required to stop the ore car in a distance of 1 meter?

- 340.3 kN/m
- 680.7 kN/m
- 980.0 kN/m
- 1960.0 kN/m

An amount of work equal to 1 J is required to compress the spring in a spring-gun. To what height can this "gun" shoot a 20-gram marble?

- 5.1 m
- 10.2 m
- 15.3 m
- 20.4 m

A 60-kg woman runs up a flight of stairs having a rise of 4 meters in a time of 4.2 seconds. What average power did she supply?

- 380 W
- 560 W
- 616 W
- 672 W

A 15.0 kg crate, initially at rest, slides down a ramp 2.0 m long and inclined at an angle of 20° with the horizontal. If there is no friction between the ramp surface and crate, what is the velocity of the crate at the bottom of the ramp? (g = 9.8 m/s2 )

- 6.1 m/s
- 3.7 m/s
- 10.7 m/s
- 8.3 m/s

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