Deck 6: Momentum and Collisions: Part A

Question 1

A force of 200 N is applied to a 50-kg mass in the direction of motion for a distance of 6.0 m,and then the force is increased to 300 N for the next 5.0 m.For the 11 m of travel,how much work is done by the varying force?

A) 2700 J
B) 1500 J
C) 2400 J
D) −1200 J

Answer 1

2700 J

Question 2

A 15.0-kg crate,initially at rest,slides down a ramp 4.0 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)

A) 200 J
B) 690 J
C) 10 J
D) 100 J

Answer 2

200 J

Question 3

A horizontal force of 100 N is applied to move a 45-kg cart across a 5.0-m level surface.What work is done by the 100-N force?

A) 405 J
B) 500 J
C) 900 J
D) 4500 J

Answer 3

500 J

Question 4

Rupel pushes a box 4.00 m by applying a 25.0-N horizontal force.What work does she do?

A) 10.0 J
B) 100 J
C) 125 J
D) 550 J

Question 5

I use a rope 1.00-m-long to swing a 1.00-kg weight around my head.The tension in the rope is 20.0 N.In half a revolution how much work is done by the rope on the weight?

A) 20.0 J
B) 31.4 J
C) 123 J
D) 0

Question 6

What is the minimum amount of energy required for a 70.0-kg climber carrying a 20.0-kg pack to climb Mt.Everest,which is 8850 m high?

A) 8.67 MJ
B) 7.81 MJ
C) 4.41 MJ
D) 0.900 MJ

Question 7

The net force acting on a 12.6-kg object is given by F_x = (8 - x)N,where F_x is in newtons and x is in meters.How much work is done on the object as it moves from x = 0 to x = 6 m?

A) 64 J
B) 30 J
C) 28 J
D) 24 J

Question 8

A satellite is held in orbit by a 3000-N gravitational force.Each time the satellite completes an orbit of circumference 80,000 km,the work done on it by gravity is:

A) 2.4 × 10⁸ J
B) 2.4 × 10¹¹ J
C) 9.6 × 10¹¹ J
D) 0

Question 9

What is the kinetic energy of a 0.160-kg ball thrown at 40.0 m/s (90.0 mph)?

A) 54.0 J
B) 64.0 J
C) 108 J
D) 128 J
E) newton-meter.

Question 10

A 10.0-kg box starts at rest and slides 6.0 m down a ramp inclined at an angle of 10° 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)

A) 6.1 m/s
B) 3.5 m/s
C) 10.7 m/s
D) 4.5 m/s

Question 11

A simple pendulum,2.00 m in length,is released from rest when the support string is at an angle of 35.0° from the vertical.What is the speed of the suspended mass at the bottom of the swing? (g = 9.80 m/s² and ignore air resistance)

A) 0.941 m/s
B) 1.88 m/s
C) 2.66 m/s
D) 1.33 m/s

Question 12

A horizontal force of 200 N is applied to a 55-kg cart across a 10 m level surface.If the cart accelerates at 3.0 m/s²,then what is the work done by the force of friction as it acts to retard the motion of the cart?

A) −900 J
B) −175 J
C) −350 J
D) −700 J

Question 13

In 1908 there was a huge explosion referred to as the Tunguska event which occurred in Siberia.Apparently this was caused by a very large meteorite,a small asteroid,or a comet colliding with the Earth.If the energy released,estimated at 5 × 10¹⁶ J,were from the kinetic energy of the object,what would have been its approximate mass if its speed had been 10⁴ m/s?

A) 10⁶ kg
B) 10⁹ kg
C) 10¹² kg
D) 10¹⁴ kg

Question 14

A rock is thrown straight up with an initial velocity of 20.0 m/s.Ignore energy lost to air friction.How high will the rock rise?

A) 41.0 m
B) 10.2 m
C) 20.4 m
D) 11.5 m

Question 15

Samantha pushes a 60-N crate up a ramp 20.0 m in length and inclined at 10° with the horizontal.What potential energy change does the crate experience?

A) 1200 J
B) 210 J
C) 600 J
D) 300 J

Question 16

A 5.00 kg ball falls from a 2.00 m-high shelf.Just before hitting the floor,what will be its kinetic energy? (g = 9.80 m/s² and assume air resistance is negligible)

A) 98.0 J
B) 49.0 J
C) 19.6 J
D) 10.0 J

Question 17

A 1200-kg automobile moving at 25 m/s has the brakes applied with a deceleration of 5.0 m/s².How far does the car travel before it stops?

A) 39 m
B) 31 m
C) 55 m
D) 63 m

Question 18

A baseball catcher puts on an exhibition by catching a 0.15-kg ball dropped from a helicopter at a height of 91 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)

A) 84 m/s
B) 38 m/s
C) 42 m/s
D) 19 m/s

Question 19

The net force acting on a 6.0-kg object is given by F_x = (12 - x)N,where F_x is in newtons and x is in meters.How much work is done on the object as it moves from x = 0 to x = 12 m?

A) 120 J
B) 72 J
C) 36 J
D) 18 J

Question 20

A professional skier reaches a speed of 39.6 m/s on a 30° ski slope.Ignoring friction,what was the minimum distance along the slope the skier would have had to travel,starting from rest?

A) 110 m
B) 160 m
C) 320 m
D) 640 m

Question 21

When a Hooke's law spring is stretched a distance 3x,how much is the increase in energy stored in it from when it was stretched a distance x? Give your answer in terms of a multiple of the energy stored in the spring when it is stretched a distance x.

A) It is 3 times as much.
B) It is 8 times as much.
C) It is 4 times as much.
D) It is 9 times as much.

Question 22

An 80,000-kg airliner is flying at 900 km/h at a height of 8.00 km.What is its total energy (kinetic + potential)if the total was 0 when the airliner was at rest on the ground?

A) 250 MJ
B) 478 MJ
C) 8770 MJ
D) 10,300 MJ

Question 23

A pole-vaulter clears 5.00 m.With what speed does he strike the mat in the landing area?

A) 2.70 m/s
B) 9.90 m/s
C) 10.8 m/s
D) 21.6 m/s

Question 24

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 3.0 m/s when at the release point,to what maximum angle will it move in the second half of its swing?

A) 36°
B) 30°
C) 19°
D) 47°

Question 25

Old Faithful geyser in Yellowstone Park shoots water hourly to a height of 30 m.With what velocity does the water leave the ground?

A) 7.0 m/s
B) 14 m/s
C) 24 m/s
D) 28 m/s

Question 26

An amount of work equal to 3.0 J is required to compress the spring in a spring-gun.What is the "launch speed" of a 15 g marble?

A) 14 m/s
B) 15 m/s
C) 18 m/s
D) 20 m/s

Question 27

A Hooke's law spring is compressed 12.0 cm from equilibrium and the potential energy stored is 36.0 J.What is the spring constant in this case?

A) 10,000 N/m
B) 5000 N/m
C) 1200 N/m
D) The correct answer is not given.

Question 28

A 50-N crate is pulled up a 5.0-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 frictional force of 20 N between the crate and the surface,what is the force applied by the worker?

A) zero
B) 50 N
C) 30 N
D) 40 N

Question 29

Which of the following is not true about potential energy?

A) Potential energy is stored energy.
B) Potential energy is related to position.
C) Potential energy is a scalar quantity.
D) Potential energy has direction.

Question 30

By how much is the energy stored in a Hooke's law spring increased when its stretch is increased from 4.00 cm to 8.00 cm?

A) 100%
B) 200%
C) 300 %
D) The correct answer is not given.

Question 31

A 2000-kg ore car rolls 50.0 m down a frictionless 10.0° 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 2.00 m?

A) 340 kN/m
B) 68.1 kN/m
C) 1700 kN/m
D) 85.1 kN/m

Question 32

A baseball outfielder throws a baseball of mass 0.15 kg at a speed of 30 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.

A) zero
B) 51 J
C) 92 J
D) 120 J

Question 33

A bobsled makes a run down an ice track starting at 66 m vertical distance up the hill.If there is no friction,what is the velocity at the bottom of the hill?

A) 27 m/s
B) 36 m/s
C) 44 m/s
D) 54 m/s

Question 34

A spring with spring constant k is used to launch a mass m up a frictionless inclined plane having angle of elevation θ.What is the maximum height reached above the starting elevation of the mass during the motion of the mass if the spring is compressed a distance d before launch?

A)

B)

C)

D)

Question 35

A hill is 200 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?

A) 98,000 J
B) −20,000 J
C) 20,000 J
D) zero

Question 36

A worker pushes a sled with a force of 40 N over a level distance of 6.0 m.If a frictional force of 16 N acts on the wheelbarrow in a direction opposite to that of the worker,what total work is done on the wheelbarrow?

A) 240 J
B) 216 J
C) 144 J
D) 96 J

Question 37

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 2.0 m/s when at the release point,what is its speed at the bottom of the swing? (g = 9.8 m/s²)

A) 2.3 m/s
B) 2.6 m/s
C) 2.8 m/s
D) 0.5 m/s

Question 38

A Hooke's law spring is compressed 12.0 cm from equilibrium,and the potential energy stored is 36.0 J.What compression (as measured from equilibrium)would result in 100 J being stored in this case?

A) 20.0 cm
B) 14.1 cm
C) 13.6 cm
D) The correct answer is not given.

Question 39

A pendulum consists of a mass m suspended from a string of length L.When the pendulum is swinging,how much greater is the mass's potential energy when the string is displaced from the vertical by the angle θ than when the mass is at the lowest position?

A) mgL​sinθ
B) mgL​cosθ
C) mgL(1 - sinθ)
D) mgL(1 - cosθ)

Question 40

A 2.00-kg ball has zero potential and kinetic energy.Maria drops the ball into a 20.0-m deep well.After the ball comes to a stop in the mud,the sum of its potential and kinetic energy is:

A) 392 J.
B) −392 J.
C) 784 J.
D) zero.

Question 41

Motor 1 does 30 J of work in 10 s,motor 2 does 2 J of work in 5 s,motor 3 does 7 J of work in 2 s,and motor 4 does 7 J of work in 3 s.List the motors in order of highest power produced to lowest power produced.

A) 2,4,1,3
B) 3,4,1,2
C) 1,3,4,2
D) 3,1,4,2

Question 42

A speed boat requires 80 kW to move at a constant speed of 12 m/s.What is the resistive force of the water at this speed?

A) 2700 N
B) 5300 N
C) 6700 N
D) 7700 N

Question 43

A parachutist of mass 50.0 kg jumps out of an airplane at a height of 800 m.The parachute deploys,and she lands on the ground with a speed of 5.0 m/s.How much energy was lost to air friction during this jump?

A) 49,400 J
B) 98,700 J
C) 391,000 J
D) 489,000 J

Question 44

An automobile delivers 30.0 hp to its wheels when moving at a constant speed of 26.0 m/s.What is the resistance force on the automobile at this speed? (1 hp = 746 watts)

A) 18,600 N
B) 410,000 N
C) 1020 N
D) 861 N

Question 45

Preston pushes a wheelbarrow weighing 500 N to the top of a 50.0-m ramp,inclined at 20.0° with the horizontal and leaves it.Tamara accidentally bumps the wheelbarrow.It slides back down the ramp,during which a 60.0-N frictional force acts on it over the 50.0 m.What is the wheelbarrow's kinetic energy at the bottom at of the ramp? (g = 9.8 m/s²)

A) 5550 J
B) 6550 J
C) 8150 J
D) 13,100 J

Question 46

A girl and her bicycle have a total mass of 40 kg.At the top of the hill her speed is 5.0 m/s.The hill is 10 m high and 100 m long.If the force of friction as she rides down the hill is 24 N,what is her speed at the bottom?

A) 5.0 m/s
B) 10 m/s
C) 11 m/s
D) She stops before she reaches the bottom.

Question 47

A 66-kg woman runs up a flight of stairs having a rise of 4.0 m in a time of 4.2 s.What average power did she supply?

A) 380 W
B) 560 W
C) 620 W
D) 670 W

Question 48

A 400-hp engine can deliver,in SI units,an average power of _____.(1 hp = 746 W)

A) 200 W
B) 74,600 W
C) 149,000 W
D) 298,000 W

Question 49

How fast would a 1000-kg car be traveling if it had a kinetic energy equal to 1000 Calories?

A) 91 m/s
B) 2.9 m/s
C) 12 m/s
D) 8 m/s

Question 50

A 1000 kg sports car accelerates from zero to 25 m/s in 6.25 s.What is the average power delivered by the automobile engine?

A) 20.8 kW
B) 30.3 kW
C) 41.7 kW
D) 50.0 kW

Question 51

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 8.0 m on each stroke.If the resisting force of the ground is 2.0 × 10⁶ N,how far is the post driven in on each stroke?

A) 4.9 cm
B) 9.9 cm
C) 16 cm
D) 49 cm

Question 52

A 100-W light bulb is left on for 20.0 hours.Over this period of time,how much energy did the bulb use?

A) 1000 J
B) 7.2 MJ
C) 3,600,000 J
D) 1.34 hp

Question 53

A 20-N crate starting at rest slides down a rough 5.0-m long ramp,inclined at 25° with the horizontal.30 J of energy is lost to friction.What will be the speed of the crate at the bottom of the incline?

A) 0.98 m/s
B) 2.1 m/s
C) 3.5 m/s
D) 4.7 m/s

Question 54

A baseball catcher puts on an exhibition by catching a 0.150-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 0.500 m while catching it,what average force is exerted on the mitt by the ball? (g = 9.80 m/s²)

A) 78 N
B) 119 N
C) 197 N
D) 295 N

Question 55

A girl and her bicycle have a total mass of 40.0 kg.At the top of the hill her speed is 5.0 m/s,and her speed doubles as she rides down the hill.The hill is 12.0 m high and 100 m long.How much kinetic energy and potential energy is lost to friction?

A) 2420 J
B) 3200 J
C) 2000 J
D) 3920 J

Question 56

A jet engine develops 2.0 × 10⁵ N of thrust in moving an airplane forward at a speed of 900 km/h.What is the power developed by the engine?

A) 500 kW
B) 10 MW
C) 25 MW
D) 50 MW

Question 57

Water flows over a section of Niagara Falls at a rate of 6.00 × 10⁵ kg/s and falls 50.0 m.What is the power dissipated by the waterfall?

A) 588 MW
B) 294 MW
C) 147 MW
D) 60.0 MW

Question 58

Yuri,a Russian weightlifter,is able to lift 300 kg a distance 2.00 m in 2.00 s.What is his power output?

A) 500 W
B) 2.45 kW
C) 2.94 kW
D) 9.80 kW

Question 59

Adisa pulls a 50-N crate up a 5.0-m long inclined plane at a constant velocity.If the plane is inclined at an angle of 37° to the horizontal and there is a constant force of friction of 10 N between the crate and the surface,what is the net change in potential energy of the crate?

A) 120 J
B) −120 J
C) 250 J
D) 150 J

Question 60

I drop a 60-g golf ball from 2.0 m high.It rebounds to 1.3 m.How much energy is lost?

A) 0.29 J
B) 0.41 J
C) 0.88 J
D) 1.0 J

Question 61

Four different compact fluorescent bulbs and their comparison to incandescent bulbs are advertised as follows: a 42-W cfl produces the light of a 150-W incandescent,a 9-W cfl produces the light of a 40-W incandescent,a 23-W cfl produces the light of a 100-W incandescent,and a 13-W cfl produces the light of a 60-W incandescent.Which cfl produces the most light per watt,and which one produces the least? Assume true advertising!

A) the 13 W,the 42 W
B) the 9 W,the 23 W
C) the 23 W,the 42 W
D) the 42 W,the 13 W