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.
Answer:
<h2>Gravity :</h2><h3>the force that attracts a body towards the centre of the earth, or towards any other physical body having mass.</h3>
<h2>Solar day</h2><h3>A solar day is the time it takes for the Earth to rotate about its axis so that the Sun appears in the same position in the sky.</h3><h2> or</h2><h3>It is the time between successive meridian transits of the sun at a particular place.</h3>
Answer:
1:4
Explanation:
The formula for calculating kinetic energy is:

If the mass is multiplied by 4, then, the kinetic energy must be increased by 4 as well. Since they will be travelling at the same speed when they are at the same point, the relation between KA and KB must be 1:4 or 1/4. Hope this helps!
Average speed = total distance / time ⇒ total distance = average speed * time
Average speed = 270 km / p hours
distance = d
hours = x
d = 270/p * x