A ball is rolled off a horizontal roof at 6m/sec , after leaving the roof how long it will take to reach a speed of 10 m/sec?

A. 0.20 seconds
B. 0.81 seconds
C. 1.8 seconds
D. 2.5 seconds

1 answer

the horizontal velocity is 6 m/s

the total velocity is the vector sum of the horizontal and vertical components

using Pythagoras, the vertical velocity must be 8 m/s
... it's a 3-4-5 triangle (6-8-10)

B looks good