The kinetic energy of a particle increases continuously with time . Then select correct alternative. ?
(A) the magnitude of its linear momentum is increasing continuously.
(B) its height above the ground must continuously decrease.
(C) the work done by all forces acting on the particle must be positive.
(D) the resultant force on the particle must be parallel to the velocity at all times.
PLEASE CLEAR ALL POINS ( Specially D)
(A) the magnitude of its linear momentum is increasing continuously.
(B) its height above the ground must continuously decrease.
(C) the work done by all forces acting on the particle must be positive.
(D) the resultant force on the particle must be parallel to the velocity at all times.
PLEASE CLEAR ALL POINS ( Specially D)
1 Answer
Given,Kinetic energy(K.E) of a particle increases with time(
So,we can write,
So,
or,
Integrating we get,
So,distance covered by the particle increases with time...b is not correct
Now, if momentum of the parcticle is
So,we can write,
So,
So, option a is correct.
Now,
So,force acting i.e
But,
So,
Again,in its pathway, The force needs not to act parallel to velocity,it can act at an angle more than
But,if the force acts perpendicularly to the direction of velocity,there will be no change in kinetic energy i.e it will become constant and it can't be more than