Question

A ball is dropped from the edge of a roof. How long does it take tofall 4.9m? (given acceleration =9.8m/s2)
What is the acceleration after 1 second and after 2 seconds after its release? (g= 9.8m/s2)

Answer 1

u = 0      and g = 9.8 m/s²
s = u t + 1/2 g t²  = 1/2 g t²

t = √(2 s / g) = √(2 * 4.9 / 9.8) = 1 sec.

acceleration is a constant as it is equal to the acceleration due to gravity of Earth and is equal to  g = 9.8 m/s²  at t = 1sec or 2 sec  or any other time.

v = u + g t  =  9.8 t
v = 9.8 m/s  after 1 sec,   and  19.6 m/s at  2 sec.
 

Answer 2

Answer:

v=u+gt=9.8 t

v=9.8 m/sec after 1 sec

and

19.6 m/sec at 2sec

Explanation:

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