A person says that he measured the acceleration of a particle to be nonzero while no force was acting on the particle.

Mass of the body = 20 kg  Initial velocity = 5 m/s  Final velocity = 2 m/s  We know that , Work done = change in kinetic energy = 1/2 mu2 - 1/2 mv2 = 1/2...

Acceleration in an object could be zero even when several forces are acting on it. This happens when all the forces cancel out each other i.e., the net force acting...

(a) never has a nonzero dimension, Explanation: A unitless quantity never has a non-zero dimension.

(b) There are other forces on the particle.  (d) The resultant of the other forces varies in magnitude as well as in direction. Explanation:  Above situation is possible when resultant of external forces...

(a) As x increases k increases.  Explanation: Since the motion is simple harmonic, the force F=-⍵²x where ⍵² is a constant. Equating the force applied by the student we get, -k/x=-⍵²x  →k=⍵²x²  It is...

(d) He might have used noninertial frame. Explanation: Because if a particle with no force acting on it is viewed from a non-inertial frame that is moving with a certain acceleration, then...

(b) v0 = 0, a0 ≠ 0,  (d) v0 ≠0,a0≠ 0. Explanation:  Since the external force is nonzero, there will be nonzero acceleration. Hence (b) and (d).  It may be at rest at time t, then (b) otherwise (d).

(a) vector r . vector T = 0 and vector F. vector T= 0 

(a) Task 1 can not be assigned to either person 1 or 2 i.e. there are 4 options. Task 2 can be assigned to 3 or 4 So, there are only 2 options...