Question

48. A ball is thrown up and attains a maximum
height of 100 m. Its initial speed was
(a) 9.8 ms-1
(c) 19.6 ms-1
(d) none of these
(b) 44.2
​

Answer 1

Answer:

44.2 m/s

Explanation:

Maximum height = 100m

Initial Speed = u

Maximum Height = u²/2g

100 = u²/ 2 × 9.8

100 = u²/19.6

1960 = u²

u = √1960

u = 44.2 m/s

Answer 2

Answer:

given,

h=100m

g=9.8m/s^2

v=0m/s. (body stops at rest)

we know that, v^2=u^2+2gh

0=u^2+2*9.8*100

0=u^2+960

u=√1960

u =44.2