Question

While adhering to social distancing guidelines, you decide to launch a pebble attack from your home-made catapult, on your friend who lives in a nearby apartment building (8m away from your window). Your friend’s window is the same height as yours.  Your launching angle is 30^o from the horizon. Use g = 9.8 m/s².

What should the initial speed be, so that the pebble hits your friend’s window. Express your answer in units of m/s, but enter only the numeric answer. Round your answer to 2 decimal places.

Answer 1

Gravitational acceleration = g = 9.8 m/s²

Initial speed of the pebble = V

Angle at which you launch the pebble = = 30^o

Distance between your window and your friend's window = R = 8 m

This can be viewed as a projectile as your window and your friend's window are at same height.

The range for a projectile is given by,

V = 9.51 m/s

Initial speed of the pebble so that the pebble hits your friend's window = 9.51 m/s