Stone **A **is projected vertically upwards at a speed of 12 m∙s^{-1} from a height h above the ground. Ignore the effects of air resistance.

3.1 Calculate the time taken for stone **A **to reach its maximum height. (3)

At the same instant that stone **A **is projected upwards, stone **B **is thrown vertically downwards from the same height at an *unknown speed, v*. Refer to the diagram below.

When stone **A **reaches its maximum height, the speed of stone **B **is 3v.

3.2 Calculate the speed, v, with which stone **B **is thrown downwards. (4)

At the instant stone **A **passes its initial position on its way down, stone **B **hits the ground.

3.3 Calculate the height * h*. (3)

3.4 Sketch velocity-time graphs for the complete motions of stones

**A**and

**B**on the same set of axes. Label your graphs for stones

**A**and

**B**clearly.

Show the following on the graphs:

• The time taken for stone

**A**to reach its maximum height

• The velocity with which stone

**B**is thrown downwards (4)

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