Question

A projectile is launched at an angle of 34.0o above the horizontal. The projectile has a mass of 1.50 kg and is given an initial speed of 20.0 m/s. a) What is the initial kinetic energy of the projectile? b) By how much does the gravitational potential energy of the projectile change as the projectile moves from its initial position to the highest vertical point in its motion? c) What is the maximum height reached by the projectile?

Answer 1

(a)
KE=(1/2)mv²

(b)
At maximum height,
KE in y-direction = 0, i.e.
loss in KE
=(1/2)m(v sin(θ))²

(c)
Maximum height, h
equate mgh to loss in KE, or
mgh = (1/2)m(v sin(θ))²

Solve for h.