Question
Tue September 24, 2013 By: Sahil Ahmed
 

(a)state the unit of force and define it. (b)a stone is dropped from the edge of a 4.9m high roof. find out the following: (1)time taken to fall 4.9m (2)velocity just before it reaches the ground. (3)what is its acceleration after 1s and 2s. please its urgent!!

Expert Reply
Romal Bhansali
Wed September 25, 2013
(a) The unit of force is newton denoted as N.
It is defined as, "One newton is the force needed to accelerate a body of mass 1 kg at a rate of 1 metre per second squared".
 
(b) u = 0, h = 4.9 m, g = 9.8 m/s2.
 
1) The time taken to fall 4.9 m is:
 
2) The velocity just before it reaches the ground is:
 
3) The body is acted upon by the acceleration due to gravity which is constant throughout the motion. Thus, the acceleration of the stone after 1s and 2 s is 9.8 m/s2.
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