Sunday, 29 April 2007

Problem: Kinematics #1

A stone is released from a height of 20 m and allowed to fall in a straight line towards the ground. Ignoring air resistance, calculate
a) the time taken for the stone to reach the ground.
b) the velocity of the stone just before it touches the ground
(Assume that g = 10 m s-2)

Solution

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1 comment:

Raymart Jay said...

Given:
d = 20.0 m
g = 10 m/s^2
vi = 0 m/s

Sol'n:
a.) d = vi*t + (g*t^2)/2
20.0 m= (0)*t + ((10 m/s^2)*t^2)/2
20.o m= (5.0 m/s^2)* t^2
4.0 s^2 = t^2
t = 2 sec

b.) vf = vi + gt
vf = 0 m/s + (10 m/s^2)*(2 s)
vf = 20 m/s