Work, Force and Energy Notes

DISADVANTAGES OF FRICTION

1. The main disadvantage of friction is that it produces heat in various parts of machines.

•      Heat produced due to friction causes damage to machine parts such as car brakes.

•      Friction causes damage to tyres of vehicles.

WORK

•      Work is said to be done when a force applied on an object causes it to move in the direction of the force.

Work = force × distance

•      We can measure work by measuring how much force, or energy, is required to move something, and multiplying that by how far it moved.

•      Activities like sleeping, thinking, reading, etc. are not considered “work” in science.

•      But, activities like playing sports, riding a horse, etc. are considered “work” in science.

ENERGY

•      The ability to do work is called energy.

•      There are many forms of energy.

Mechanical energy:

•      The energy which is possessed by an object due to its motion or its stored energy of position is called mechanical energy.

•      Mechanical energy can be either kinetic energy (energy of motion) or potential energy (stored energy of position).

For example: