Two workmen are employed on a building project, as shown in figure

cbse
cbse-class-9-science
work-and-energy

#1

Two workmen are employed on a building project, as shown in figure.
image

  1. Workman 1 drops a hammer, which falls to the ground. The hammer has a mass of 2.0 kg, and is dropped from a height of 4.8 m above the ground.
  • Calculate the change in gravitational potential energy of the hammer when it is dropped.
  • Describe the energy changes from the time the hammer leaves the hand of 3 workman 1 until it is at rest on the ground.
  1. Workman 2 picks up the hammer and takes it back, up the ladder to workman 1. He climbs the first 3.0 m in 5.0 s. His total weight, including the hammer, is 520 N.
    Calculate the useful power which his legs are producing.
    Answer:
    image