Question

The bulldog and skateboard have a combined mass of 20 kg. In case B (the middle of the three pictures of the bulldog and the well), the bulldog and skateboard have a KE of 380 J at the bottom of the well. How deep is the well in meters?

Answer 1

h = 1.94 m

Step-by-step explanation:

When the bull dog and skate board reach the bottom of the well, all of its potential energy is converted to the kinetic energy:

Kinetic Energy Gained by Bull Dog and Skate Board = Potential Energy Lost by Bull Dog and Skate Board

K.E = P.E

K.E = mgh

h = K.E/mg

where,

h = depth of well = ?

K.E = Kinetic Energy at bottom = 380 J

m = mass of bull dog and skate board = 20 kg

g = 9.8 m/s²

Therefore,

h = 380 J/(20 kg)(9.8 m/s²)

h = 1.94 m