Question

1 a) Define momentum. Give its unit.
b) Why do bicycles begin to slowdown when we stop pedaling?
c) A bullet of mass 0.02 kg is fired from a gun weighing 7.5 kg. If the initial velocity of the bullet
is 200 m/s. Calculate the speed with which the gun recoils.

2 a) Calculate the power of an electric motor that can lift 800 kg of water to store in a tank at height
of 1500 cm in 20s. (g=10 m/s?).
ii) An electric heater of 1000 W is used for two hours in a day. What is the cost of using it for a
month of 28 days, if one unit costs 3.00 Rupees.
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Answer 1

Answer:

1.a) momentum is the product of mass into velocity.

unit-- kg m/s

b) the frictional force takes place between the tyre of the cycle and the road this slows down the speed of cycle and eventually stops the cycle.