1.5.2. Turning effect of forces
A subsection of Physics, 0625, through 1. Motion, forces and energy
Listing 10 of 170 questions
shows a tyre hanging from the branch of a tree. 2.5 m P branch rope tyre The mass of the tyre is 15 kg. Calculate its weight. weight of tyre = N The weight of the tyre exerts a moment on the branch, about point P where the branch joins the tree. Explain what is meant by the term moment. A child sits on the tyre. The weight of the child and tyre together is 425 N. Calculate the moment of this force about point P. Use information given in . Include the unit. moment = A heavier child wants to sit on the tyre. Describe how the tyre position should be adjusted so that the moment is the same as in .
0625_s17_qp_31
THEORY
2017
Paper 3, Variant 1
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A man uses a metal bar to remove an iron nail from a piece of wood, as shown in . nail wood pivot 150 N 0.50 m The man applies a force of 150 N at a distance of 0.50 m from the pivot. Calculate the moment of this force about the pivot. Include a unit. moment = The force applied by the man produces a turning effect about the pivot. Describe another example of using the turning effect of a force. The man tries to use the metal bar to remove another nail from the piece of wood. He applies the same force of 150 N at a distance of 0.50 m from the pivot. The turning effect produced is not enough to remove this nail from the piece of wood. Describe how the man can increase the turning effect without increasing the force.
0625_s18_qp_32
THEORY
2018
Paper 3, Variant 2
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shows a wheelbarrow and shows the dimensions of its wheel. pivot load 1.50 m 35 cm = diameter of wheel 25 mm = diameter of axle Complete the table to show the diameter of the wheel and axle in metres. measurement measurement in metres diameter of wheel 35 cm diameter of axle 25 mm The mass of the wheelbarrow is 20 kg. The mass of the load in the wheelbarrow is 30 kg. Calculate the total weight of the wheelbarrow and its load. weight of wheelbarrow and load = N A man lifts the handle of the wheelbarrow. He applies a force of 140 N, as shown in . wheelbarrow handle 140 N 1.30 m pivot Calculate the moment of the force about the pivot. Include the unit. moment =
0625_s19_qp_33
THEORY
2019
Paper 3, Variant 3
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shows a sign that extends over a road. 1.8 m W 1.3 m concrete block P 70 cm support post sign ACCIDENT SLOW DOWN The mass of the sign is 3.4 × 103 kg. Calculate the weight W of the sign. W = The weight of the sign acts at a horizontal distance of 1.8 m from the centre of the support post and it produces a turning effect about point P. Point P is a horizontal distance of 1.3 m from the centre of the support post. Calculate the moment about P due to the weight of the sign. moment = A concrete block is positioned on the other side of the support post with its centre of mass a horizontal distance of 70 cm from the centre of the support post. 1. State what is meant by centre of mass. 2. The weight of the concrete block produces a moment about point P that exactly cancels the moment caused by the weight W. Calculate the weight of the concrete block. weight = The concrete block is removed. The sign and support post rotate about point P in a clockwise direction. State and explain what happens to the moment about point P due to the weight of the sign as it rotates.
0625_s19_qp_41
THEORY
2019
Paper 4, Variant 1
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Questions Discovered
170