10 A ball is thrown upwards with a velocity of \(29.4 \mathrm {~m} \mathrm {~s} ^ { - 1 }\).
- Show that the ball reaches its maximum height after 3 s .
- Sketch a velocity-time graph for the first 5 s of motion.
- Calculate the speed of the ball 5 s after it is thrown.
A second ball is thrown at \(u \mathrm {~m} \mathrm {~s} ^ { - 1 }\) at an angle of \(\alpha ^ { \circ }\) above the horizontal. It reaches the same maximum height as the first ball.
- Use this information to write down
- the vertical component of the second ball's initial velocity,
- the time taken for the second ball to reach its greatest height.
This second ball reaches its greatest height at a point which is 48 m horizontally from the point of projection. - Calculate the values of \(u\) and \(\alpha\).