Pearson Edexcel International GCSE (9–1) · PHYSICS · Section
THE TURNING EFFECT OF FORCES
24 practice questions
Practice questions
1–10 of 13 · Normal
Question 1
4 marks · Normal
Answer and see the solution →A person tries to open a heavy gate by applying a force of 120 N perpendicular to the gate, 0.75 m from the hinge. Another person tries to keep the gate closed by pushing with a force of 180 N, but only 0.3 m from the hinge.
(a)[1 mark]Calculate the moment produced by the first person about the hinge.
(b)[1 mark]Calculate the moment produced by the second person about the hinge.
(c)[2 marks]State which person has a greater turning effect on the gate and explain your answer.
Question 2
4 marks · Normal
Answer and see the solution →The diagram shows a uniform beam of length 2.0 m and negligible mass balanced on two supports, A and B, at either end. A box of mass 20 kg is placed 0.5 m from support A.
Beam with supports and load (a)[1 mark]Draw a force diagram showing the forces acting on the beam.
(b)[2 marks]Taking moments about support A, calculate the upward force on support B due to the box only. (Take g = 10 N/kg.)
(c)[1 mark]State and explain how the upward forces at supports A and B would change if the box is moved closer to support B.
Question 3
1 mark · Normal
Answer and see the solution →In a uniform ruler, where does the weight act? State the name of the point.
Question 4
1 mark · Normal
Answer and see the solution →Which change will increase the moment of a force about a given pivot?
- A.Increase the force applied.
- B.Move the force closer to the pivot.
- C.Use a lighter object.
- D.Reduce the perpendicular distance from the pivot.
Question 5
4 marks · Normal
Answer and see the solution →A uniform beam is 3.0 m long and weighs 120 N. It is supported horizontally at its two ends, P and Q. A load of 90 N is placed 2.0 m from end P.
(a)[2 marks]Taking moments about end P, calculate the upward force at support Q.
(b)[2 marks]Calculate the upward force at support P.
Question 6
1 mark · Normal
Answer and see the solution →Explain the meaning of the term 'pivot' in the context of turning effects of forces.
Question 7
4 marks · Normal
Answer and see the solution →A uniform plank of wood is 4.0 m long and has a weight of 200 N. It rests horizontally on two supports placed 0.5 m from each end.
Wooden plank supported near each end (a)[1 mark]Calculate the distance from Support 1 to the centre of gravity of the plank.
(b)[3 marks]Determine, using the principle of moments about Support 1, the upward force at Support 2.
Question 8
2 marks · Normal
Answer and see the solution →Explain why it is easier to loosen a tight bolt using a spanner with a long handle rather than a short one.
Question 9
4 marks · Normal
Answer and see the solution →A mechanic uses a wrench to loosen a bolt. The wrench is 0.30 m long, and he applies a force of 150 N perpendicular to the wrench at its end.
(a)[2 marks]Calculate the moment produced by the mechanic about the centre of the bolt.
(b)[2 marks]Explain what would happen to the moment if the mechanic applied the same force closer to the centre of the bolt.
Question 10
2 marks · Normal
Answer and see the solution →State what is meant by the 'centre of gravity' of a body, and describe how the weight of a body acts with respect to this point.