What is the work done by the force of gravity on a satellite moving round the earth? Justify your answer.
When the satellite moves around the earth, the force of gravity acts on it along the radius of its orbit. The direction of motion is along the tangent to the orbit at any point. Thus, force acts perpendicular to displacement. Therefore, the work done on the satellite is zero.
What are the various energy transformations that occur when you are riding a bicycle?
Does the transfer of energy take place when you push a huge rock with all your might and fail to move it ? Where is the energy you spend going?
An object of mass 40 kg is raised to a height of 5 m above the ground. What is its potential energy ? If the object is allowed to fall, find its kinetic energy when it is half-way down.
A certain household has consumed 250 units of energy during a month. How much energy is this in joules?
