Kinematics Tutorial 2 Exercise 1 Freefall due to Gravity I A

Kinematics Tutorial 2 Exercise 1: Freefall due to Gravity I A ball is dropped from rest at a height of 2 m. Find the time that the ball takes to fall to the ground, if it is: (a) on the Earth, (b) on the Moon, where g = 1.6 m s-2

Solution

1. in vertical, initial velocity, v0 = 0

y = 0 - 2 = - 2 m

(A) a= - 9.81 m/s^2

Applying y = v0 t + a t^2 /2

-2 = 0 - 9.81 t^2 /2

t =0.64 sec

(B) a = - 1.6 m/s^2

- 2 = 0 - 1.6 t^2 /2

t = 1.58 sec