Q23. Object is thrown vertically upwards and has a speed of 18 m/s when it reaches one-fourth of its maximum height h above its launch point. Label the relevant points and answer the following;

Question

a) Determine the maximum height h.

b) What is the initial speed of throwing the object?

Answer 1

at h/4
total mechanical energy
= m g(h/4)+(1/2)m (18)^2

at h
total mechanical energy
= m g h + 0

so
gh = gh/4 + 9*18

for part b
(1/2)m v^2 = m g h