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.
<span>The following that describes the intercepts on the graph is "The initial velocity of the runner was 4 m/s, and the runner stopped after 8 seconds." It is because the starting point of the line is at 4 and then the ending point is at 8.
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Proceed with caution before crossing
a. speed b. direction c. Magnitude d. Direction
U=6.9ms-¹
a=0.62ms-²
t=3.4s
V=?
using
v=u+at
v=6.9+(0.62×3.4)
v= 6.9+2.108
v=9.008ms-¹