Question

A target lies flat on the ground 11 m from the side of a building that is 10 m tall, as shown below. The acceleration of gravity is 10 m/s 2 . Air resistance is negligible. A student rolls a 11 kg ball off the horizontal roof of the building in the direction of the target. The horizontal speed v with which the ball must leave the roof if it is to strike the target is most nearly:

1. v =11√3/3m/s.
2. v = 11√2 m/s.
3. v =√2/11m/s.
4. v = 11√5 m/s.
5. v = 2√11 m/s.
6. v =√3/11m/s.
7. v =√5/11m/s.
8. v = 3√11 m/s.
9. v = 11√3 m/s.

Answer 1

Step-by-step explanation:

Given in the y direction:

s = 10 m

u = 0 m/s

a = 10 m/s²

Find: t

s = ut + ½ at²

10 = (0) t + ½ (10) t²

t = √2 s

Given in the x direction:

s = 11 m

a = 0 m/s²

t = √2 s

Find: u

s = ut + ½ at²

11 = u (√2) + ½ (0) (√2)²

u = 11/√2 m/s