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Mechanics Questions
Friction, Inclined Planes
Question 1
| The system below is in equilibrium. Frictional forces can be neglected. |
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| a) |
Given that m2 = 0·2kg, calculate m1. |
| b) |
Calculate the gravitational potential energy gained by m1 if m2 is pushed down 0·3m. |
| c) |
If m1 is removed and replaced by an object of mass 2m1, calculate the acceleration of the system. |
| d) |
Calculate the total kinetic energy of the system after 2s of acceleration (with the mass 2m1 in place and assuming that vo = 0). |
Question 2
| A body rests, without slipping, on a plane which is inclined at 30° to the horizontal. |
| a) |
Draw a diagram showing the forces acting on the body. |
| b) |
If the body has a mass of 2kg, calculate the magnitude of the force of friction acting on it. |
Question 3
| An object of mass m = 5kg is being pulled up an inclined plane which is at 40° to the horizontal. The object is pulled at a constant speed of 0·8ms-1 by a force which acts parallel to the inclined plane. The coefficient of friction between the object and the plane is 0·2. |
| a) |
Draw a diagram showing the forces acting on the object. |
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b) |
Calculate the magnitude of the force of friction acting on the object. |
| c) |
Calculate the gain in g.p.e. when the object has moved 0·5m (measured parallel to the slope). |
| d) |
Calculate the total work done in pulling the block 0·5m (measured parallel to the slope). |
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