Chapter #3 :Motion : Short Q/A / C.R.Q's

Q. It is observed that all bodies sliding down a frictionless inclined plane have the same acceleration. How does it happen?

Ans. The acceleration of any body sliding down the inclined plane is given by

            a= g Sinθ

            This formula is showing that the acceleration of any body is independent of the mass or radius or something else .It only depends on the value of g and the angle of inclined surface with the horizontal.

Q. Can an object has zero velocity and still have acceleration?

Ans.Yes, When a body is vibrated and it is at the extreme position its velocity is zero. But the acceleration is maximum.

            Another example is that when the body is at the maximum height it has the velocity zero but has acceleration equal to g.

Q. If two spheres of different size and mass are roll down the inclined plane without friction, which will reach the down first?

Ans. The acceleration of any body sliding down the inclined plane is given by

            a= g Sinθ

            This formula is showing that the acceleration of any body is independent of the mass or radius or something else .It only depends on the value of g and the angle of inclined surface with the horizontal.

Q. If two forces are acting on a body then what is the condition that (1) The body has Constant Velocity (2) Constant Speed

Ans.If two forces are acting on a body and their resultant is non zero then it has acceleration and the change in velocity is due to the change in direction with constant speed i.e. in the circular motion. And if the resultant of two forces is equal to zero then the body has constant velocity

Q. Does the speed of a body be negative?

Ans. No, Speed is a scalar quantity .Or it only represents the magnitude but not the direction so speed can never be a negative quantity.

Q. What is the acceleration of the bodies with masses 10Kg and 20Kg while they are dropped from same height?

Ans. During free fall motion the acceleration of a body becomes equal to the acceleration due to gravity and it does not depends on the mass it only depends on the height so if two bodies are falling from same height so both will have the same acceleration.