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2 marksEffects of Forces

CAPE Physics Unit 1 · 2011 · Paper 2 · Question 1(a)(ii)

A skydiver of mass m falls under gravity and a drag force Fd = bv^n, where v is velocity, b is a constant, and n is an integer. Figure 1 shows the skydiver.

Hence show that when her downward acceleration is a, the equation of motion for the skydiver can be written as g - a = (b/m)v^n.

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Other parts of this question

  1. 1(a)(i)Next to Figure 1 draw a free body diagram to show the forces acting on the skydiver.[1 mark]
  2. 1(b)(i)Complete Table 1 by filling in the blank columns.[3 marks]
  3. 1(b)(ii)On page 4, plot a graph of lg (g – a) vs lg v.[3 marks]
  4. 1(b)(iii)Calculate the gradient of the graph and hence determine a value for n (to the nearest integer).[3 marks]
  5. 1(b)(iv)Calculate the terminal velocity of a skydiver with a mass of 78.5 kg, given that b = 0.251 kg m⁻¹.[3 marks]

More practice: the rest of this paper · more Effects of Forces questions · all CAPE Physics Unit 1 past papers