How A ball is dropped from rest according the diagram below
Solution
There are two problems and the value of the total height in the first problem is not clear ;next time please upload image with more resolution , but we solve the 2 problems assuming the total height is 3.0 m in 1st problem
1) the velocity of the ball after reaching 1.5 m is gained by converting the potential into kinetic energy
the potential energy converted to kinetic form at 1.5 m can be given by
potential enrgy of the ball = m g (3.0 m-1.5 m ) = m v^2 / 2
9.8 * 1.5 = v ^2 / 2
v = 29.4 m/ sec
by the time the ball fall to ground all the gravitational potential energy is converted to kinetic energy
the potential enrgy of the ball falling from hight = mgh = kinetic energy = mv^2/ 2 , m is mass , v is velocity
from above equation v = sqrt (2gh)
v = 7.668 m/sec
2nd problem
Potential energy of the block at a height h = weight * height = mg * h (weight = mg ) m is mass , g is acceleration due to gravity
Potential energy = 73N*24m = 1752 Joules
