Power - Questions II.2.1
- If an engine does 1500 J of work in 2.0 minutes, what is its power in watts?
- An engine with a power of 250 W must do a job that requires 145 000 J. How long will it take to do this job?
- A construction worker is working at a rate of 450 W. How much work will he do in 25 min?
- How much power is needed to do 50 J of work on an object in 12 s? How much power is needed if the same work is done in 6 s?
- Calculate the power expended by a weight lifter when a 420 N barbell is lifted 1.8 m in 1.5 s.
- A dancer that weighs 760 N is lifted a distance of 12.0 m straight up by a rope. What power is developed if takes 12 s to lift the dancer?
- An amateur rock climber wears a 3.4 kg backpack while scaling a cliff. After 45 min she is 8.4 m above the starting point.
- How much work did she do on the backpack?
- If the climber weighed 790 N, how much work did she do lifting herself and the backpack?
- What would be the average power developed by the climber?
- Determine the power of a race car if its average velocity is 210 km/h and the applied force is 820 N.
- Determine the power of a bulldozer if it pushes a rock with a force of 7 500 N at 1.8 m/s for 35 s.
- How much work was done by the bulldozer?