9702_s12_qp_11
A paper of Physics, 9702
Questions:
40
Year:
2012
Paper:
1
Variant:
1
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12
The diagram shows a barrel suspended from a frictionless pulley on a building. The rope supporting the barrel goes over the pulley and is secured to a stake at the bottom of the building. stake 18 m barrel 120 kg man 80 kg A man stands close to the stake. The bottom of the barrel is 18 m above the man’s head. The mass of the barrel is 120 kg and the mass of the man is 80 kg. The man keeps hold of the rope after untying it from the stake and is lifted upwards as the barrel falls. What is the man’s upward speed when his head is level with the bottom of the barrel?
3. Dynamics  →  3.1. Momentum and Newton’s laws of motion
6. Deformation of solids  →  6.1. Stress and strain
2. Kinematics  →  2.1. Equations of motion
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15
The diagram shows a crane supporting a load L. L W x y R A mass provides a balancing load W. The position of the load is such that the system is perfectly balanced with Wx = Ly. The ground provides a reaction force R. The distance x does not change. If the load is moved further out so that the distance y increases and the crane does not topple, which statement is correct?
4. Forces, density and pressure  →  4.2. Equilibrium of forces
6. Deformation of solids  →  6.2. Elastic and plastic behaviour
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32
Lightning can occur between a charged cloud and the Earth’s surface when the electric field strength in the intervening atmosphere reaches 25 kN C–1. The diagram shows the electric field between the base of a cloud and the Earth’s surface. base of cloud Earth’s surface 2 km – + + + + + + + + + + + – – – – – – – – – – What is the minimum potential difference between the Earth and the base of a cloud, 2 km high, for lightning to occur?
18. Electric fields  →  18.5. Electric potential
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