ch 6 problems physics

certain car traveling at 34.0 mph skids to a stop in 29 meters from the point where the brakes were applied. In approximately what distance would the car have stopped had it been going 105.4 mph? A) 279 m B) 158 m C) 90 m D) 51 m E) 29 m

a

A 1000-kg car is moving at 15 km/h. If a 2000-kg truck has 23 times the kinetic energy of the car, how fast is the truck moving? A) 51 km/h B) 72 km/h C) 61 km/h D) 41 km/h

A

How much work must be done by frictional forces in slowing a 1000-kg car from to rest? A) 3.41 × 105 J B) 2.73 × 105 J C) 4.09 × 105 J D) 4.77 × 105 J

A

How much work would a child do while pulling a 12-kg wagon a distance of with a force? A) 95 J B) 52 J C) 67 J D) 109 J

A

What is the minimum energy needed to change the speed of a 1600-kg sport utility vehicle from 15.0 m/s to 40.0 m/s? A) 1.10 MJ B) 10.0 kJ C) 20.0 kJ D) 40.0 kJ E) 0.960 MJ

A (1/2*MV^2)

When a car of mass accelerates from 10.0 m/s to some final speed, 4.00 × 105 J of work are done. Find this final speed. A) 28.0 m/s B) 22.4 m/s C) 25.2 m/s D) 30.8 m/s

A, (1/2*m*(vf^2 - vi^2)

A 30-N box is pulled upward 6.0 m along the surface of a ramp that rises at 37° above the horizontal. How much work does gravity do on the box during this process? A) -1100 J B) -110 J C) -140 J D) -180 J E) 120 J

B

A 340-g air track cart traveling at 1.25 m/s suddenly collides elastically with a stationary 300-g cart. What is the speed of the 300-g cart just after the collision? A) 0.0781 m/s B) 1.33 m/s C) 0.625 m/s D) 1.25 m/s E) 0.664 m/s

B

A bead is moving with a speed of 20 m/s at position A on the track shown in the figure. This track is friction-free, and there is no appreciable air resistance. What is the speed of the bead at point C? A) 0 m/s B) 34 m/s C) 69 m/s D) 20 m/s E) We cannot solve this problem without knowing the mass of the bead

B

A sled having a certain initial speed on a horizontal surface comes to rest after traveling 10 m. If the coefficient of kinetic friction between the object and the surface is 0.20, what was the initial speed of the object? A) 9.8 m/s B) 6.3 m/s C) 3.6 m/s D) 7.2 m/s E) 8.9 m/s

B

A 550-g ball traveling at 8.0 m/s undergoes a sudden head-on elastic collision with a 250-g ball traveling toward it also at 8.0 m/s. What is the speed of the 250-g mass just after the collision? A) 15 m/s B) 8.0 m/s C) 4.0 m/s D) 14 m/s E) 0 m/s

D

) An object initially at rest suddenly explodes in two fragments of masses and that move in opposite directions. If the speed of the first fragment is find the internal energy of the explosion. A) 30 J B) 30 kJ C) 38 J D) 38 kJ

a

A tennis ball bounces on the floor three times, and each time it loses 23.0% of its energy due to heating. How high does it bounce after the third time, if we released it from the floor? A) 180 cm B) 18 cm C) 180 mm D) 240 cm

a

An 8.0-g bullet is suddenly shot into a 4.0-kg block, at rest on a frictionless horizontal surface, as shown in the figure. The bullet remains lodged in the block. The block then moves against a spring and compresses it by 8.9 cm. The force constant (spring constant) of the spring is What is the magnitude of the impulse on the block (including the bullet inside) due to the spring during the entire time interval during which the block compresses the spring? A) 13 N ∙ s B) 12 N ∙ s C) 10 N ∙ s D) 8.3 N ∙ s E) 6.7 N ∙ s

a

An ideal spring with a spring constant (force constant) of is stretched from equilibrium to 2.9 m. How much work is done in the process? A) 93 J B) 186 J C) 47 J D) 121 J

a

As shown in the figure, a 1.45-kg block is held in place against the spring by a 21-N horizontal external force. The external force is removed, and the block is projected with a velocity as it separates from the spring. The block descends a ramp and has a velocity at the bottom. The track is frictionless between points A and B. The block enters a rough section at B, extending to E. The coefficient of kinetic friction between the block and the rough surface is 0.29. The velocity of the block is at C. The block moves on to D, where it stops. How much work is done by friction between points B and C? A) -1.8 J B) -3.6 J C) -14 J D) -6.4 J E) -7.0 J

a

Assuming negligible friction, what spring constant (force constant) would be needed by the spring in a "B-B gun" to fire a 10-g pellet to a height of 100 m if the spring is initially compressed by 0.10 m? A) 20 N/cm B) 20 N/m C) 200 N/m D) 2000 N/cm E) 0.0020 N/m

a

A traveler pulls on a suitcase strap at an angle 36° above the horizontal. If of work are done by the strap while moving the suitcase a horizontal distance of what is the tension in the strap? A) 46 N B) 37 N C) 52 N D) 56 N

a (WORK DONE= FORCE X DISTANCE X COS(ANGLGE))

left side of a loop-the-loop, as shown in the figure. There is no appreciable friction from the track or from air resistance. If the radius of the loop is R, what is the minimum height h for which the stone will not fall off the track at the top of the loop? A) 3.5 R B) 2.5 R C) 2.0 R D) R E) 3.0 R

b

A 100-N force has a horizontal component of 80 N and a vertical component of 60 N. The force is applied to a cart on a level frictionless floor. The cart starts from rest and moves 2.0 m horizontally along the floor due to this force. What is the cart's final kinetic energy? A) 200 J B) 160 J C) 120 J D) zero

b (w=f*d*cosx)

A 5.0-N projectile leaves the ground with a kinetic energy of 220 J. At the highest point in its trajectory, its kinetic energy is 120 J. To what vertical height, relative to its launch point, did it rise if there was no air resistance? A) 44 m B) 24 m C) 20 m D) 10 m E) It is impossible to determine the height without knowing the angle of launch.

c

A small 1.4-N stone slides down a frictionless bowl, starting from rest at the rim. The bowl itself is a hemisphere of radius 75 cm. Just as the stone reaches the bottom of the bowl, how hard is the bowl pushing on it? A) 0.70 N B) 1.4 N C) 2.8 N D) 4.2 N E) 5.6 N

d

13) A person carries a 2.00-N pebble through the path shown in the figure, starting at point A and ending at point B. The total time from A to B is 6.75 min. How much work did gravity do on the rock between A and B? A) 30.0 J B) -30.0 J C) -56.0 J D) 56.0 J E) -36.0 J

-30

An object hits a wall and bounces back with half of its original speed. What is the ratio of the final kinetic energy to the initial kinetic energy of the object? A) 1/2 B) 1/4 C) 1/8 D) 1/16

B

A proton of mass m is at rest when it is suddenly struck head-on by an alpha particle (which consists of 2 protons and 2 neutrons) moving at speed v. If the collision is perfectly elastic, what speed will the alpha particle have after the collision? (Assume the neutron's mass is equal to the proton's mass.) A) zero B) 2v/3 C) 3v/5 D) 5v/3

C

A rock falls from a vertical cliff that is 4.0 m tall and experiences no significant air resistance as it falls. At what speed will its gravitational potential energy (relative to the base of the cliff) be equal to its kinetic energy? A) 3.1 m/s B) 4.4 m/s C) 6.3 m/s D) 8.9 m/s E) 13 m/s

C

A stone with a mass of 1.0 kg is tied to the end of a light string which keeps it moving in a circle with a constant speed of 4.0 m/s on a perfectly smooth horizontal tabletop. The radius of the path is 0.60 m. How much work does the tension in the string do on the stone as it makes one-half of a complete circle? A) 100 J B) 3.8 J C) 0 J D) 40 J E) 80 J

C

) An 8.0-g bullet is suddenly shot into a 4.0-kg block that is at rest on a frictionless horizontal surface, as shown in the figure. The bullet remains lodged in the block. The block then moves against a spring and compresses it by 3.7 cm. The force constant (spring constant) of the spring is What was the initial speed v of the bullet? A) 460 m/s B) 440 m/s C) 480 m/s D) 500 m/s E) 520 m/s

a

131) Planet X-39 has a mass equal to 1/3 that of Earth and a radius equal to 1/3 that of Earth. If V is the escape speed for Earth, what is the escape speed for X-39? A) V B) 3V C) 6V D) V/9 E) 9V

a

50) A block slides down a frictionless inclined ramp and experiences no significant air resistance. If the ramp angle is 17.0° above the horizontal and the length of the surface of the ramp is find the speed of the block as it reaches the bottom of the ramp, assuming it started sliding from rest at the top. A) 10.7 m/s B) 114 m/s C) 7.57 m/s D) 19.6 m/s

a

A 0.12-kg block is held in place against the spring by a 35-N horizontal external force. The external force is removed, and the block is projected with a velocity when it separates from the spring, as shown in the figure. The block descends a ramp and has a velocity at the bottom of the ramp. The track is frictionless between points A and B. The block enters a rough section at B, extending to E. The coefficient of kinetic friction between the block and the rough surface is 0.26. The block moves on to D, where it stops. By how many centimeters was the spring initially compressed? A) 0.49 cm B) 0.26 cm C) 0.18 cm D) 0.99 cm E) 0.67 cm

a

A 1000-kg car experiences a net force of 9500 N while slowing down from 30 m/s to How far does it travel while slowing down? A) 34 m B) 31 m C) 37 m D) 41 m

a

A 1321-kg car climbs a 5.0° slope at a constant speed of Assuming that air resistance may be neglected, at what rate (in kW) must the engine deliver energy to the drive wheels of the car? A) 25 kW B) 287 kW C) 38 kW D) 48 kW

a

A 30-N stone is dropped from a height of 10 m and strikes the ground with a speed of 13 m/s. What average force of air friction acted on the stone as it fell? A) 4.1 N B) 2.9 N C) 0.13 kN D) 7.2 N E) 1.2 N

a

A 50-g ball moving at 10 m/s in the +x direction suddenly collides head-on with a stationary ball of mass 100 g. If the collision is perfectly elastic, what is the velocity of each ball immediately after the collision? A) -3.3 m/s, +6.7 m/s B) +3.3 m/s, -6.7 m/s C) -6.7 m/s, +3.3 m/s D) +6.7 m/s, -3.3 m/s

a

A block of mass m = 3.6 kg, moving on a frictionless surface with a speed makes a sudden perfectly elastic collision with a stationary block of mass M, as shown in the figure. Just after the collision, the 3.6-kg block recoils with a speed of What is the speed V of the other block? A) 6.6 m/s B) 8.0 m/s C) 9.3 m/s D) 10.7 m/s E) 12.0 m/s

a

A block of mass m = 4.4 kg, moving on frictionless surface with a speed makes a sudden perfectly elastic collision with a second block of mass M, as shown in the figure. The second block is originally at rest. Just after the collision, the 4.4-kg block recoils with a speed of What is the mass M of the second block? A) 7.7 kg B) 0 kg C) 0 kg D) 0 kg E) 0 kg

a

A block of mass m = 9.0 kg and speed V and is behind a block of mass M = 27 kg and speed of as shown int the figure. The surface is frictionless, and the blocks suddenly collide and couple. After the collision, the blocks have a common speed of 0.90 m/s. How much kinetic energy of the blocks is lost due to the collision? A) 8.6 J B) 2.0 J C) 4.6 J D) 11 J E) 31 J

a

A child pulls on a wagon with a force of If the wagon moves a total of in what is the average power delivered by the child? A) 17 W B) 21 W C) 22 W D) 26 W

a

A crane lifts a 425 kg steel beam vertically upward a distance of How much work does the crane do on the beam if the beam accelerates upward at 1.8 m/s2? Neglect frictional forces. A) 4.7 × 105 J B) 2.7 × 105J C) 3.2 × 105 J D) 4.0 × 105 J

a

A prankster drops a water balloon from the top of a building. If the balloon is traveling at 29.1 m/s when it strikes a window ledge that is 1.5 m above the ground, how tall is the building? Neglect air resistance. A) 45 m B) 43 m C) 46 m D) 47 m

a

A spring-loaded dart gun is used to shoot a dart straight up into the air, and the dart reaches a maximum height of 24 meters. The same dart is shot up a second time from the same gun, but this time the spring is compressed only half as far (compared to the first shot). How far up does the dart go this time (neglect all friction and assume the spring is ideal)? A) 6.0 m B) 12 m C) 3.0 m D) 48 m

a

An ideal spring has a spring constant (force constant) of 60 N/m. How much energy does it store when it is stretched by 1.0 cm? A) 0.0030 J B) 0.30 J C) 60 J D) 600 J

a

An ideal spring stretches by 21.0 cm when a 135-N object is hung from it. If instead you hang a fish from this spring, what is the weight of a fish that would stretch the spring by A) 199 N B) 91 N C) 145 N D) 279 N

a

If electricity costs 7.06¢/kW∙h, how much would it cost you to run a stereo system per day for A) $0.95 B) $0.14 C) $1.62 D) $2.66

a

In a ballistics test, a 28-g bullet pierces a sand bag that is thick. If the initial bullet velocity was and it emerged from the sandbag moving at what was the magnitude of the friction force (assuming it to be constant) that the bullet experienced while it traveled through the bag? A) 130 N B) 38 N C) 13 N D) 1.3 N

a

It takes 87 J of work to stretch an ideal spring from 1.4 m to 2.9 m from equilibrium. What is the value of the spring constant (force constant) of this spring? A) 27 N/m B) 77 N/m C) 52 N/m D) 39 N/m

a

On an alien planet, an object moving at 4.0 m/s on the horizontal ground comes to rest after traveling a distance of 10 m. If the coefficient of kinetic friction between the object and the surface is 0.20, what is the value of g on that planet? A) 4.0 m/s2 B) 6.0 m/s2 C) 8.0 m/s2 D) 10 m/s2 E) 12 m/s2

a

Planet W-70 has a radius of 2.48 × 107 m and an escape velocity of 23,300 m/s. What is the mass of W-70? (G = 6.67 × 10-11 N ∙ m2/kg2) A) 1.01 × 1026 kg B) 2.02 × 1026 kg C) 3.03 × 1026 kg D) 4.04 × 1026 kg E) 5.05 × 1026 kg

a

The value of g at the surface of spherical Asteroid X is 0.00600 m/s2, and the escape speed is 9.95 m/s. What is the radius of this asteroid? (G = 6.67 × 10-11 N ∙ m2/kg2) A) 8250 m B) 16,000 m C) 1600 m D) 800 m E) 400 m

a

To what radius would the sun have to be compressed in order for it to become a black hole? The mass of the sun is 1.99 × 1030 kg, G = 6.67 × 10-11 N ∙ m2/kg2, and c = 3.00 × 108 m/s A) 2950 m B) 1470 m C) 6.96 × 108 m D) 2.66 × 106 m E) 3.72 × 104 m

a

Two simple pendulums of equal length l = 0.45 m are suspended from the same point. The pendulum bobs are small solid steel spheres. The first bob is drawn back to make a 35° angle with the vertical, while the other one is left hanging at rest. If the first bob has a mass of 0.25 kg and the second has a mass of how high will the second bob rise above its initial position when struck elastically by the first bob after it is released? A) 3.3 cm B) 2.7 cm C) 3.9 cm D) 4.4 cm

a

You carry a 7.0-kg bag of groceries above the ground at constant speed across a room. How much work do you do on the bag in the process? A) 0.00 J B) 82 J C) 185 J D) 157 J

a

You do 116 J of work while pulling your sister back on a fritctionless swing, whose chain is long, until the swing makes an angle of 32.0° with the vertical. What is your sister's mass? A) 15.3 kg B) 13.0 kg C) 17.6 kg D) 19.0 kg

a

Find the net work done by friction on a box that moves in a complete circle of radius on a uniform horizontal floor. The coefficient of kinetic friction between the floor and the box is 0.25, and the box weighs A) 190 J B) 0 J C) 1800 J D) 370 J

a (WORK DONE BY FRICTINO IN A CIRCLE= W= f(2PIR)

It requires 0.30 kJ of work to fully drive a stake into the ground. If the average resistive force on the stake by the ground is how long is the stake? A) 0.36 m B) 0.23 m C) 0.31 m D) 0.41 m

a (w=Fd)

A 10-kg mass, hung by an ideal spring, causes the spring to stretch 2.0 cm. What is the spring constant (force constant) for this spring? A) 5.0 N/cm B) 49 N/cm C) 0.20 N/cm D) 20 N/m E) 0.0020 N/cm

b

A 320-g air track cart traveling at 1.25 m/s suddenly collides elastically with a stationary 270-g cart. What is the speed of the 320-g cart just after the collision? A) 0.68 m/s B) 0.11 m/s C) 0.21 m/s D) 1.4 m/s E) 1.1 m/s

b

A 60-kg skier pushes off the top of a frictionless hill with an initial speed of 4.0 m/s. How fast will she be moving after dropping 10 m in elevation? Air resistance is negligible. A) 0.20 km/s B) 15 m/s C) 10 m/s D) 0.15 km/s E) 49 m/s

b

A toy rocket that weighs 10 N blasts straight up from ground level with an initial kinetic energy of 40 J. At the exact top of its trajectory, its total mechanical energy is 140 J. To what vertical height above the ground does it rise, assuming no air resistance? A) 1.0 m B) 10 m C) 14 m D) 24 m

b

An 825-kg space vehicle is circling Earth in a circular orbit with a radius of 10,300 km. Its orbit is to be changed to a larger circle with a radius of 17,400 km. How much energy is required to accomplish this? The mass of Earth is 5.97 × 1024 kg and G = 6.67 × 10-11 N ∙ m2/kg2. A) 1.00 × 109 J B) 1.30 × 1010 J C) 6.51 × 109 J D) 4.45 × 109 J E) 4.50 × 1010 J

b

At what minimum rate is a 60.0-kg boy using energy when, in 8.00 s, he runs up a flight of stairs that is 10.0-m high? A) 75.0 W B) 735 W C) 4.80 kW D) 48.0 W

b

How many joules of energy are used by a 1.0-hp motor that runs for 1.0 hour? (1 hp = 746 W) A) 3.6 kJ B) 2.7 MJ C) 45 kJ D) 4.8 J

b

In a police ballistics test, a 2.00-g bullet suddenly hits and becomes embedded in a 5.00-kg wood block which is hanging from a 1.20-m long string. This causes the block to swing through an arc of 3.50°. What was the speed of the bullet just before it hit the block? A) 16.7 m/s B) 524 m/s C) 25.3 m/s D) 262 m/s E) 789 m/s

b

The figure shows a famous roller coaster ride. You can ignore friction. If the roller coaster leaves point Q from rest, what is its speed at the top of the 25-m peak (point S)? A) 10 m/s B) 22 m/s C) 44 m/s D) 62 m/s E) 120 m/s

b

) A projectile is shot straight up from the surface of Earth by means of a very powerful cannon and experiences no appreciable air resistance. If the projectile reaches a height of 35,000 m above Earth's surface, what was the speed of the projectile when it left the cannon? (G = 6.67 × 10-11 N ∙ m2/kg2, the radius of Earth is 6.38 × 106 m, and Mearth = 5.97 ∙ 1024 kg) A) 355 m/s B) 505 m/s C) 827 m/s D) 710 m/s E) 906 m/s

c

) In the figure, a ball hangs by a very light string. What is the minimum speed of the ball at the bottom of its swing (point B) in order for it to reach point A, which is 1.0 m above the bottom of the swing? A) 2.2 m/s B) 3.1 m/s C) 4.4 m/s D) 4.9 m/s

c

) What is the minimum energy needed to lift a 1.0-kg rocket to a height of 200 km and to give it a speed of 8.0 km/s at that height? (Neglect air resistance and the small decrease in g over that distance.) A) 34 TJ B) 34 kJ C) 34 MJ D) 34 GJ E) 34 J

c

A 0.140-kg baseball is dropped from rest from a height of 2.20 m above the ground and experiences negligible air resistance as it falls. It rebounds to a height of 1.60 m. What change in the ball's momentum occurs as it rebounds from the ground? A) 0.117 kg ∙ m/s upwards B) 0.117 kg ∙ m/s downwards C) 1.70 kg ∙ m/s upwards D) 0.350 kg ∙ m/s upwards E) 0.350 kg ∙ m/s downwards

c

A 2.0-kg mass moving at 5.0 m/s suddenly collides head-on with a 3.0-kg mass at rest. If the collision is perfectly inelastic, what is the speed of the masses just after the collision? A) 10 m/s B) 2.5 m/s C) 2.0 m/s D) 0 m/s, since the collision is inelastic

c

A 320-g air track cart traveling at 1.25 m/s suddenly collides elastically with a stationary 270-g cart. What is the speed of the 270-g cart just after the collision? A) 0.678 m/s B) 0.106 m/s C) 1.36 m/s D) 1.14 m/s E) 2.72 m/s

c

A 60-kg skier starts from rest from the top of a 50-m high slope. If the work done by friction is -6.0 kJ, what is the speed of the skier on reaching the bottom of the slope? A) 17 m/s B) 24 m/s C) 28 m/s D) 31 m/s

c

A driver, traveling at 22 m/s, slows down her 2000 kg truck to stop for a red light. What work is done on the truck by the friction force of the road? A) -2.2 × 104 J B) -4.4 × 104 J C) -4.8 × 105 J D) -9.7 × 105 J

c

A roller coaster starts from rest at a height h at the left side of a loop-the-loop, as shown in the figure. It is not attached to the track in anyway, and there is no friction from the track or from air resistance. If the radius of the loop is R = 6.0 m, what is the minimum height h for which the roller coaster will not fall off the track at the top of the loop? A) 21 m B) 18 m C) 15 m D) 12 m E) 8.5 m

c

Asteroid X is 0.0060 m/s2 and the escape velocity is 10.1 m/s. What is the mass of this asteroid? (G = 6.67 × 10-11 N ∙ m2/kg2) A) 2.3 × kg B) 3.5 × kg C) 6.5 × kg D) 4.9 × kg E) 6.7 × kg

c

In a certain nuclear reactor, neutrons suddenly collide with carbon nuclei, which have 12 times the mass of neutrons. In a head-on elastic collision with a stationary carbon nucleus, what fraction of its initial speed does the neutron have after the collision? A) 11/12 B) 1/12 C) 11/13 D) 5/6 E) 10/13

c

On a planet where g = 10.0 m/s2 and air resistance is negligible, a sled is at rest on a rough inclined hill rising at 30° as shown in the figure. The object is allowed to move and it stops on a rough horizontal surface, at a distance of 4.0 m from the bottom of the hill. The coefficient of kinetic friction on the hill is 0.40. What is the coefficient of kinetic friction between the horizontal surface and the sled? A) 0.10 B) 0.20 C) 0.31 D) 0.40 E) 0.60

c

The kinetic friction force that a horizontal surface exerts on a 60.0-kg object is 50.0 N. If the initial speed of the object is 25.0 m/s, what distance will it slide before coming to a stop? A) 15.0 m B) 30.0 m C) 375 m D) 750 m

c

Three masses are located as follows: a 3.0-kg mass is at the origin, a 4.5-kg mass at (0.0 m, 4.0 m) and a 2.5-kg mass at (3.0 m, 0.0 m). What is the gravitational potential energy of this system of masses? (G = 6.67 × 10-11 N ∙ m2/kg2) A) -3.8 × 10-10 J B) -3.9 × 10-10 J C) -5.4 × 10-10 J D) -3.2 × 10-10 J E) -3.5 × 10-10 J

c

A stone initially moving at 8.0 m/s on a level surface comes to rest due to friction after it travels 11 m. What is the coefficient of kinetic friction between the stone and the surface? A) 0.13 B) 0.25 C) 0.30 D) 0.43 E) 0.80

c (first find a)

) A 1200-kg pick-up truck traveling south at 15 m/s suddenly collides with a 750-kg car that is traveling east. The two vehicles stick together and slide along the road after colliding. A highway patrol officer investigating the accident determines that the final position of the wreckage after the collision is 25 m, at an angle of 50° south of east, from the point of impact. She also determines that the coefficient of kinetic friction between the tires and the road at that location was 0.40. What was the speed of the car just before the collision? A) 20 m/s B) 4.8 m/s C) 14 m/s D) 23 m/s E) 17 m/s

d

) As shown in the figure, a bullet of mass 0.010 kg moving horizontally suddenly strikes a block of wood of mass 1.5 kg that is suspended as a pendulum. The bullet lodges in the wood, and together they swing upward a vertical distance of 0.40 m. The length of the string is 2.0 m. What was the speed of the bullet just before it struck the wooden block? A) 67 m/s B) 250 m/s C) 370 m/s D) 420 m/s E) 650 m/s

d

A 1500-kg car accelerates from rest to 25 m/s in 7.0 s. What is the average power delivered by the engine? (1 hp = 746 W) A) 60 hp B) 70 hp C) 80 hp D) 90 hp

d

A 1500-kg car moving at 25 m/s hits an initially uncompressed horizontal ideal spring with spring constant (force constant) of 2.0 × 106 N/m. What is the maximum distance the spring compresses? A) 0.17 m B) 0.34 m C) 0.51 m D) 0.68 m

d

A certain battery charger uses 12 W of power. At 6.0 cents per kilowatt-hour, how much does it cost to charge batteries for a full day? A) 28¢ B) 1.4¢ C) 75¢ D) 1.7¢ E) 2.3¢

d

A sand mover at a quarry lifts 2,000 kg of sand per minute a vertical distance of 12 m. The sand is initially at rest and is discharged at the top of the sand mover with speed 5.0 m/s into a loading chute. What minimum power must be supplied to this machine? A) 520 W B) 3.9 kW C) 6.7 kW D) 4.3 kW E) 1.1 kW

d

A stone is moving on a rough level surface. It has 24 J of kinetic energy, and the friction force on it is a constant 0.50 N. What is the maximum distance it can slide? A) 2.0 m B) 12 m C) 24 m D) 48 m

d

An ideal spring with a force constant (spring constant) of 15 N/m is initially compressed by 3.0 cm from its uncompressed position. How much work is required to compress the spring an additional 4.0 cm? A) 0.0068 J B) 0.012 J C) 0.024 J D) 0.030 J

d

An object with a mass of 10 kg is initially at rest at the top of a frictionless inclined plane that rises at 30° above the horizontal. At the top, the object is initially 8.0 m from the bottom of the incline, as shown in the figure. When the object is released from this position, it eventually stops at a distance d from the bottom of the inclined plane along a horizontal surface, as shown. The coefficient of kinetic friction between the horizontal surface and the object is 0.20, and air resistance is negligible. Find the distance d. A) 5.0 m B) 10 m C) 15 m D) 20 m E) 25 m

d

If the work done to stretch an ideal spring by 4.0 cm is 6.0 J, what is the spring constant (force constant) of this spring? A) 300 N/m B) 3000 N/m C) 3500 N/m D) 7500 N/m E) 6000 N/m

d

In a museum exhibit of a simple pendulum, a very small but dense 6.0-kg ball swings from a very light 2.5-m wire. The ball is released from rest when the pendulum wire makes a 65° angle with the vertical, and it swings in a circular arc with no appreciable friction or air resistance. What is the tension in the wire just as the ball swings through its lowest position? A) 11 N B) 59 N C) 68 N D) 130 N E) 0 N

d

What mass would have to be compressed to a radius of 1.0 × 10-15 m (the order of magnitude of the radius of an atomic nucleus) in order for it to become a black hole? (G = 6.67 × 10-11 N ∙ m2/kg2, c = 3.0 × 108 m/s) A) 1.1 × 10-6 kg B) 4.1 × 10-8 kg C) 2.2 × 103 kg D) 6.7 × 1011 kg E) 8.3 × 1015 kg

d

A small but dense 2.0-kg stone is attached to one end of a very light rod that is 1.2 m long. The other end of the rod is attached to a frictionless pivot. The rod is raised until it is vertical, with the stone above the pivot. The rod is released and the stone moves in a vertical circle with no air resistance. What is the tension in the rod as the stone moves through the bottom of the circle? A) 20 N B) 40 N C) 60 N D) 80 N E) 100 N

e

An ideal spring has a spring constant (force constant) of 2500 N/m. is stretched 4.0 cm. How much work is required to stretch the spring by 4.0 cm? A) 4.0 J B) 0.00 J C) 1.0 J D) 3.0 J E) 2.0 J

e

How large a net force is required to accelerate a 1600-kg SUV from rest to a speed of 25 m/s in a distance of 200 m? A) 1600 N B) 0 N C) 200 N D) 400 N E) 2500 N

e

If 4.0 J of work are performed in stretching an ideal spring with a spring constant (force constant) of 2500 N/m, by what distance is the spring stretched? A) 3.2 cm B) 3.2 m C) 0.3 cm D) 5.7 m E) 5.7 cm

e

If a spring-operated gun can shoot a pellet to a maximum height of 100 m on Earth, how high could the pellet rise if fired on the Moon, where g = 1.6 m/s2? A) 17 m B) 160 m C) 3.6 km D) 100 m E) 610 m

e

In a certain nuclear reactor, neutrons suddenly collide with deuterons, which have twice the mass of neutrons. In a head-on elastic collision with a stationary deuteron, what fraction of the initial kinetic energy of a neutron is transferred to the deuteron? A) 1/2 B) 1/3 C) 3/4 D) 5/6 E) 8/9

e

What is the net power needed to change the speed of a 1600-kg sport utility vehicle from 15.0 m/s to 40.0 m/s in 4.00 seconds? A) 100 kW B) 10.0 kW C) 140 kW D) 14.0 kW E) 275 kW

e