A boy throws a ball vertically upwards from a point A with an initial speed of 18·2ms–1.
(c) Find the speed of the ball 2·5 s after it was thrown. State clearly the direction of motion of the ball at this time.
Here also we can use equations of motion as we have done in part (a).
`uarrV = U+at`
`uarrV = 18.2-9.81xx2.5 `
`uarrV = 18.2-9.81xx2.5`
`uarrV = -6.325m/s`
Velocity of the ball is 6.325m/s.
We have used the motion equation in the upward direction. The final velocity gives is a negative value. That means the direction of the ball is at the opposite direction.
So the ball goes downward towards the ground at 2.5 seconds after it was thrown.