Question

A stone is throne vertically upwards with an initial velocity of 20m/sec. The maximum height it reaches and the time taken by to reaches the height (g=10m/s)

Answer 1

Answer:

s = 20m , t = 2s

Explanation:

u = 20 m/s

v = 0 m/s (it comes to rest at a certain height)

a = 10 m/s^2 (gravity)

s = ?

v^2 = u^2 - 2as

0^2 = 20^2 - 2(10)s

0 = 400 - 20s

-400 = - 20s

400/20 = s

20 = s

therefore, 20m is the maximum height reached by the stone.

v = u + at

0 = 20 + 10t

20/10 = t

2 = t

therefore, 2s of time is taken to cover 20 m of distance

Answer 2

Initial velocity (u)=20m/s

Final velocity (v)=0

acceleration=10m/s

=a=v-u

t

=0-20m/s

10m/s

= -20m/s

10m/s

=-2m/s-2