A student standing on a cliff that is a vertical height d = 8.0 m above the level ground throws a stone with velocity v0 = 15 m/s at an angle θ = 31 ° below horizontal. The stone moves without air resistance; use a Cartesian coordinate system with the origin at the stone's initial position.

Required:
With what speed, vf in meters per second, does the stone strike the ground?

Explanation:

The initial vertical velocity of the stone is given by:

Vyo= VSin theta

Given: V = 15m/s , theta = 31°

Vyo = 15 Sin 31

Vyo = 7.73m/s

Final vertical velocity, Vf can be determined by using kinematic equation

Vf^2 - U^2 = 2as

Vf^2 -( 7.73)^2 = 2(9.8×(-8))

Vf^2 = 59.75 + 156.8

Vf^2 = 216.6

Vf = sqrt(216.46)

Vf = 14.72m/s

Therefore,The stone strikes the ground in 14.72m/s

resonant frequency