28. How much work is done lifting a 3-m chain over the side of a building if the chain has mass density 4 kg/m?

A student with a mass of 50.0 kg climbs a vertical staircase in 28.5 seconds. If the staircase has 14.0 steps and each step is 22.5 cm high, calculate his power output. (Answer to 1 decimal place) Your Answer: Answer units

1. A box with a mass of 3.0 kg is accelerated from rest by a constant force across a floor at a rate of 1.7 m/s for 6.5 s. (a) How much work does the force do on the box? (b) How much power is produced by the force in moving the box?

A 2,000-kg pile driver is used to drive a steel I-beam into the ground. The pile driver falls 3.00 m before coming into contact with the top of the beam, and it drives the beam 14.6 cm farther into the ground as it comes to rest. Using energy considerations, calculate the average force the beam exerts on the pile driver while the pile driver is brought to rest.