Question 3

A small disc, C, is thrown vertically upwards at a speed of 15 m∙s^-1 from the edge of
the roof of a building of height 30 m. AFTER 0,5 s, a small ball B is shot vertically upwards from the foot of the building at a speed of 40 m∙s^-1 in order to hit disc C.
Ignore the effects of air resistance.

3.1 Explain the term projectile. (2)

3.2 Calculate the:
3.2.1 Time taken by disc C to reach its maximum height (3)

3.2.2 Maximum height above the ground reached by disc C (4)

3.3 Calculate the time from the moment that disc C was thrown upwards until
the time ball B hits the disc. (6)

3.4 On the same set of axes, sketch graphs of velocity versus time for disk C and ball B from the moment that disc C was thrown upwards until ball B hits disc C.
Label the graph for ball B as B and the graph for disc C as C.

Clearly indicate the following on the graphs:
– The initial velocities of ball B and disc C
– The time at which ball B was shot upward
– The time at which disc C reaches its maximum height
– The time at which ball B hits disc C (5)
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