Name ______________________________________________Date____________________Period_________ Power practice problems Work (J) = Force (N) X distance (m) Power (Watts) = Work (J) Time (sec) KgN (multiply by 9.8) cm m (divide by 100) 1. A game show contestant won a prize by pushing a bowling ball 20m using his nose. The amount of work done was 1470 J. How much force did the person exert on the ball? 2. You family is moving to a new apartment. It takes you 1 second to lift a 200 N box straight up onto a truck that is 1.5 meters off the ground. How much power did you exert? 3. You lift a book from the floor to a bookshelf 100cm above the ground. How much power is used if the book is 0.5kg and you do the work in 2 seconds? 4. A carpenter lifts a 45 kg beam 1.2 meters. How much work is done on the beam? 5. A dancer lifts a 400 N ballerina overhead a distance of 1.4m and holds her there for several seconds. How much work is done during the lift? How much work is being done while the ballerina is being held? Explain. 6. A weight lifter lifts a 1,250N barbell 2 m in 3seconds. How much power was used to lift the bar? How much power does it take to hold the barbell overhead? Explain.