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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

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.

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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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  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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.

  18. The unit of work, joule, is dimensionally the same as which of the following? • newton/second • newton/kilogram • newton-second • newton-meter

  19. The unit of power, watt, is dimensionally the same as which of the following? • joule-second • joule/second • joule-meter • joule/meter

  20. The rate at which work is done is equivalent to which of the following? • increase in potential energy • thermal energy • potential energy • power

  21. 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

  22. 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

  23. 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

  24. Which of the following is an example of a non-conservative force? • gravity • magnetism • Both magnetism and gravity • friction

  25. Which of the following is that form of energy associated with an object's motion? • potential • thermal • bio-chemical • kinetic

  26. 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

  27. 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

  28. 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

  29. The quantity of work equal to one joule is also equivalent to which of the following? • watt • watt/s • watt x s • watt/s2

  30. 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

  31. 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

  32. 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

  33. 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

  34. 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.

  35. 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

  36. 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

  37. 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

  38. 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

  39. 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

  40. 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.

  41. 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

  42. 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

  43. 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

  44. 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

  45. 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.

  46. 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°

  47. 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

  48. 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

  49. The work done by static friction is always • positive • negative • along the surface • zero

  50. 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

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