A projectile is hit with speed 20 m/s at some angle, and it reaches a velocity of 3 m/s at the highest point. Calculate the time needed by this projectile to reach the ground if it is shot from the roof of a building 29m high.

H=19.95m

Explanation:

Using 3rd equation of motion

V^2=u^2+2gh

g is negative since redardation is produced.

3^2=20^2-2×9.8×h

9=400-19.6h

391=19.6h

h=19.95m

second mirror gathers light from a faraway object and reflects it to another mirror. - a.