Question

A block of mass $40gm$ is moving with a constant velocity of $2cm/s$ on a horizontal frictionless table. The force on the table by the block is (Take $g=10m/s^2$)

• A. none of these
• B. $0.40N$ downwards
• C. net force on the table by block is zero
• D. $0.40N$ upwards

Answer 1

The correct option is B $0.40N$ downwards

Draw FBD for block and table.

Find force on the table by the block.

Given, mass of the block, $m=400gm=0.04kg$
As the block is moving with constant velocity, so its horizontal acceleration will be zero.
And in vertical direction, $N=mg$
So, force on table by the block,
$N=mg$
$=0.04\times 10$
$=0.4N$ (downwards)