Definitions [9]
Define the term “weight of a body”
The weight of the body is the force with which the earth attracts it towards the centre. It depends on acceleration due to gravity.
Answer the following.
Define weight.
The gravitational force acting on an object is called the weight of the object.
A force is applied between two objects even if the two objects are not in contact; such a force is called a 'Non-contact force.'
OR
The forces experienced by a body without any physical contact with another object, e.g., gravitational force, electrostatic force, are called non-contact forces.
A force is seen to act through direct contact of the objects or via one more object. Such a force is called 'Contact force.'
OR
The forces experienced by a body due to physical contact with another object, e.g., frictional force, normal force, are called contact forces.
Answer the following in short.
Define force. Write its SI unit.
A push or pull acting upon an object as a result of its interaction with another object is called force. Its SI unit is the newton (N).
Define static friction
The maximum force exerted by a surface on a body so long as it remains stationary is called the force of static friction.
Define rolling friction
The minimum force required to roll a body on a surface is called the force of rolling friction.
Define sliding friction
The minimum force required to keep the body moving over a surface such that it moves equal distances in equal intervals of time is called the force of sliding friction.
"Friction between two bodies in contact when one body is rolling over the other, is called rolling friction."
