Explanation:
The work done on the body = force applied x displacement
in this case , the acceleration of body a = [tex]\frac{Force}{Mass}[/tex] = [tex]\frac{4.9}{14}[/tex] = 0.35 ms⁻²
The displacement in first second S₁ = u + [tex]\frac{1}{2}[/tex] a x t²
here u = 0 , because body was at rest
Thus S₁ = [tex]\frac{1}{2}[/tex] x 0.35 x ( 1 )² = = 0.175 m
The work done = 4.9 x 0.175 = 0.86 J
The displacement in 2 seconds = [tex]\frac{1}{2}[/tex] x 0.35 x ( 2 )² = 0.7 m
Work done in 2 seconds = 4.9 x 0.7 = 3.43 J
Work done in second second = 3.43 - 0.86 = 2.57 J
The displacement in three seconds = [tex]\frac{1}{2}[/tex] x 0.35 x ( 3 )² = 1.575 m
Work done in three seconds = 4.9 x 1.575 = 7.7 J
Work done in third second = 7.7 - 3.43 = 4.3 J
The power at the end of third second is 4.3 watt
Because 4.3 J of work is done in the last second .
