Question

A cannonball is fired horizontally at 20 m/s from a cliff. Its speed 2 seconds after being fired is about _________ m/s

A cannonball is fired horizontally at 20 m/s from a cliff. Its speed 2 seconds after being fired is about m/s Answer in m/s

Answer 1

The vertical component of the velocity increases in the downward direction.
According the following formula Vf=Vi+g*t , After 2s, the vertical component of the velocity will be 9.8×2=19.6 m/s.
The horizontal component of the velocity remains unchanged 20m/s.
The velocity can be calculated by the formula V = √(Vx^2+Vy^2) , where Vx – the horizontal component of the velocity and Vy – the vertical component of the velocity.
Finally, V=√{(V_x)^2+(V_y)2}

V=√[400+384.16]

V= 28 m/s