Question

A stone is thrown vertically upward with a speed of
40 m/s. The time interval for which particle was
above 40 m from the ground is (g = 10 m/s2)

Answer 1

Explanation:

s = ut+1/2at^2

40= 40t+1/2×10×t^2

40=40t+5t^2

5t^2+40t-40

t^2+8t-8

Answer 2

Answer:4sqrt2

Explanation:s=ut+1/2*at^2

40=0+1/2*10*t^2

40/10=1/2t^2

4=1/2t^2

4*2=t^2

sqrt{8}=t

4*sqrt2=t