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A brass ball is hanging from a stiff cotton thread. Draw a neat labelled diagram showing the forces acting on the brass ball and cotton thread.
A brass ball is hanging thus, weight mg of ball acts downwards and tension acts on the thread in the upward direction.
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The distance between two bodies is doubled. How is the magnitude of the gravitational force between them affected?
Force of gravity given by
Therefore, the force of gravity is reduced four times.
Why is a jack screw provided with a long arm?
A jack, screw jack or jackscrew is a mechanical device used as a lifting device to lift heavy loads or to apply great force. A jack screw is provided with a long arm in order to have the effort less than the load.
Moment of force (torque, which is responsible for turning effect of the body)
Rotation is given by the moment
Torque = Force x perpendicular length
Therefore, the long arm of the jack screw, the more force it can apply.
If the power of a motor is 100 kW, at what speed can it raise a load of 50,000 N?
Given, power of the motor, P = 100 kW =100 × 1000 W = 105 Watt
and force, F = 50000 N.
Now, from the definition of power,
Hence, the motor can lift the load with a speed of 2 ms-1.
Which class of lever will always have MA > 1 and why?
A second Class lever (class II) will always have MA > 1. This is because the load is between the fulcrum and the effort. So, the effort arm is always greater than the load arm. Hence, MA = E/L > 1.
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Mock Test Series
