A stone is thrown vertically upward with a speed of 24.0 ms. (a) How fast is it moving when it reaches a height of 13.0 m? (b) How much time is required to reach this height?

Question A:17.92 m/s

Question B:0.6 seconds

Explanation:

Question A:

Initial velocity (u) = 24m/s

Height (h) = 13m

acceleration due to gravity (g) = 9.8m/s^2

Final velocity=v

v^2=u^2-2xgxh

v^2=24^2-2x9.8x13

v^2=24x24-2x9.8x13

v^2=576-254.8

v^2=321.2

Take them square root of both sides

v=√ (321.2)

v=17.92m/s

Question B:

velocity (v) = 17.92m/s

Acceleration due to gravity (g) = 9.8m/s^2

Initial velocity (u) = 24m/s

Time=t

v=u-gxt

17.92=24-9.8xt

Collect like terms

9.8t=24-17.92

9.8t=6.08

Divide both sides by 9.8

9.8t/9.8=6.08/9.8

t=0.6 approximately