Question

A steady 45 N horizontal force is applied to a 15 kg object a table. The object slides against a friction force of 30 N. Calculate the acceleration of the object in m/s.

Answer 1

The net force on an object subject to friction is equal to the sum of the applied force and the frictional force.

Mathematically,

`F_(N) = ma = F_(applied) - f_(fr)`

Here, m is mass of object and a is its acceleration. We take frictional force negative because it opposes the motion of object.

Given,
`m=15\ kg` ,
`F_(applied) =45\ N` and
`f_(fr) = 30\ N`

Substituting these values in above formula, we get

`15\ kg* a = 45\ N -30\ N=15\ N \\\\a=(15\ N)/(15\ kg) =1\ m/s^2`.

Thus, the acceleration of an object is
`1\ m/s^2.`