A)How much work is done by a force of 80 N in moving an object through a distance of 5 m in the direction of the force? b)300 J of work is done on a body to cause a displacement of 12 m.How much force is applied on the body?
c)100 J of work is done by a force of 10 N in moving an object in the direction of the force.Calculate the displacement of the body.
d)Calculate the work done in lifting 300 kg of water from a well through a height of 20 m
[g=9.8 m/s2]
e)Calculate the vertical height through which a body of mass 10 kg is lifted when 1470 J of work is done in lifting it.[g=9.8 m/s2]
f)Calculate the power of an electric bulb which does an electric work of 800 J in 20 s.
g)Calculate the potential energy possessed by a body of mass 15 kg at a height of 20 m.
[g=9.8 m/s2]
h)The kinetic energy of a moving body of mass 10 kg is 8000 J.Calculate its velocity.
i)A body of mass 8 Kg falls from a height of 20 m.If g=9.8 m/s2 What is the potential energy possessed by the body at that height?What is its kinetic energy just before touching the ground.
j)Name the energy change i) in a room heater ii)charging of a mobile battery iii)burning of cooking gas iv)Photosynthesis.
k)State the two conditions under which work done is zero giving one example for each.
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