Question

Name the force that always opposes motion.
A. Electrostatic
B. Frictional force
C. Magnetic force
D. Muscular force

Answer 1

Hint: We can solve this problem with the concept of friction force. There are many forces in nature such as gravitational force, nuclear force, friction force, magnetic force etc. Pull or push acting upon a body which results in the interaction of the body with another object.

Complete step-by-step answer:
Newton’s second law of motion describes the force, according to this law force is the rate of change of moment with respect to time or it is pushed or pulled upon the body by which the body accelerates. Formula for its representation: $F=ma$ where $m$ is the mass of the body and $a$ is the acceleration of the body.
Friction force is the force which acts between the two surfaces that have relative motion with respect to each other and it always opposes the relative motions. In simple words, friction force acts between the two sliding surfaces or trying to slide across each other. It is a non-conservative force because work done by it is path dependent. There are two types of friction force: static friction and kinetic friction. Static friction offers more resistance than the kinetic friction.
Formula for calculation of friction force: $f=\mu N$ where $f$ is the friction force acting on the body, $\mu$ is the coefficient of friction and $N$ is the normal force acting on the body.
For the given question, friction force is more suitable because it always opposes the motion, hence the option B is correct.

Note: Force can move a stationary object or prevent the motion of an object. Forces have the capacity to change the speed and direction of a moving object. Friction force depends upon the area contact of the surface and smoothness or roughness of the surfaces.