An engineer wants to estimate the depth of a deep, vertical mine shaft.
She proposes to calculate this by dropping a heavy brass plumb bob from rest at the top of the shaft and timing how long it takes to strike the bottom.
Explain how she could use this time measurement to determine the depth of the shaft.
It takes 3.4 seconds3.4\text{ seconds}3.4 seconds for the brass bob to fall from rest and strike the bottom. Find the speed of the bob immediately before impact. (Take g=9.8 m/s2g = 9.8\text{ m/s}^2g=9.8 m/s2.)
Describe the motion of the brass bob as it falls. Assume that the bob does not reach terminal velocity during its fall. In your answer, you should describe the forces acting on the bob, including their directions and relative magnitudes, and explain how they affect its acceleration.
50 exam-style questions on OCR GCSE Physics Motion. Each one has a worked solution and a mark scheme showing where the marks go.