Here if we assume that there is no air friction on both balls then we can say
now the acceleration is given as
so here both the balls will have same acceleration irrespective of size and mass
so we can say that to find out the time of fall of ball we can use
now from above equation we can say that time taken to hit the ground will be same for both balls and it is irrespective of its mass and size
Explanation:
Given that,
The mass of rock, m = 2.35-kg
It was released from rest at a height of 21.4 m.
(a) The kinetic energy is given by :
As the rock was at rest initially, it means, its kinetic energy is equal to 0.
(b) The gravitational potential energy is given by :
It can be calculated as :
(c) The mechanical energy is equal to the sum of kinetic and potential energy such that,
M = 0 J + 492.84 J
M = 492.84 J
Hence, this is the required solution.