Question

A particle is projected vertically upwards with a speed of 16m/s, after some time, when it again passes through the point of projection, its speed is found to be 8m/s. It is found that the work done by air resistance is same during upward and downward motion. Then the maximum height attained by the particle is –

• A. 8m
• B. 4.8m
• C. 17.6m
• D. 12.8m

Answer 1

Answer: (A)

8m

Answer 2

From work energy theorem

for upward motion,

$\frac { 1 } { 2 }$ m (16)² = mgh + W

for downward motion

$\frac { 1 } { 2 }$m (8)² = mgh – W

h = 8m