Select the correct option(s).

Options

A. (a) A single external force acting on a particle necessarily changes its momentum and kinetic energy.
B. (b) A single external force acting on a particle necessarily changes its momentum.
C. (c) The work-energy theorem is valid for all types of forces: internal, external, conservative as well as non-conservative.
D. (d) The kinetic energy of the system can be increased without applying any external force on the system.

Answer

B, C, D

Explanation

Single force on a particle may change the magnitude and or direction of velocity, so momentum changes necessarily but kinetic energy may or may not change.
From work-energy theorem,
`DeltaK=W_(ext)+W_(i nt)+W_(conservative) +W_(NC)`
Kinetic energy can be increased due to work done by internal forces also.