A metre scale is moving with uniform velocity. This implies

Options

A. the force acting on the scale is zero, but a torque about the centre of mass can act on the scale.
B. the force acting on the scale is zero and the torque acting about centre of mass of the scale is also zero.
C. the total force acting on it need not be zero but the torque on it is zero.
D. neither the force nor the torque need to be zero.

Answer

B

Explanation

The force acting on the scale is zero and the torque acting about centre of amss of the scale is also zero .
By using Newton second law of motion
as scale moves with uniform velocity hence
`Delta v=0`
`Delta p = m Delta v = m ( 0) = 0`
`F= (Delta p )/( Delta t ) = 0`
Hence all the parts of scale moving with uniform velocity hence total force is zero .
`:.` Torque will be zero.