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Lesson: Power

Worksheet: Power • 25 Questions

Q1:

Some workers are loading boxes in the back of a truck. Each box has a mass of 75 kg and the height of the truck is 1 m. Given that the average total power that the group can work at is 0.5 hp, calculate the number of boxes they can load into the truck in a minute. Take .

Q2:

A car of mass 7.26 tonnes was ascending a section of road inclined to the horizontal at an angle whose sine is 0.01 at its maximum speed of 39 km/h. The resistance to the car’s motion was 20 kg-wt for each ton of the car’s mass. Determine the power of the engine assuming it is constant, and find the maximum speed the car can descend the same road. Consider the acceleration due to gravity to be 9.8 m/s2.

  • A,
  • B,
  • C,
  • D,

Q3:

The combined mass of a cyclist and their bike is 64 kg. The greatest power the cyclist can produce is horsepower. Given that the maximum speed of the cyclist on a horizontal section of road is 18 km/h, calculate the resistance to their motion in kilogram-weight. If the cyclist started ascending a hill inclined to the horizontal at an angle whose sine is , what would their maximum speed be in kilometres per hour?

  • A,
  • B,
  • C,
  • D,

Q4:

A vehicle of mass 3 tonnes was moving at 51 km/h along a horizontal section of road. When it reached the bottom of a hill inclined to the horizontal at an angle whose sine is 0.5, it continued moving at the same speed up the road. Given that the resistance of the two sections of road is constant, determine the increase in the vehicle’s power to the nearest horsepower. Take the acceleration due to gravity .

Q5:

A car of mass 2.1 tonnes was moving along a horizontal section of road at its maximum speed of 60 km/h. When the car reached the top of a section of road that was inclined to the horizontal at an angle whose sine is 0.5, the driver put the car in neutral and coasted down the hill. Given that the car kept moving at the same speed and that the resistance of the two roads was the same, determine the power of the car’s engine, rounding your answer to the nearest horsepower. Consider the acceleration due to gravity to be 9.8 m/s2.

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