Ncert Exercises & Solutions

A body of mass 5 kg is acted upon by two perpendicular forces 8 N and 6 N. Give the magnitude and direction of the acceleration of the body.

Mass of the body, m = 5 kg

The given situation can be represented as follows:

The resultant of two forces is given as:

$R = \sqrt{{(8)}^{2} + {(- 6)}^{2}} = \sqrt{64 + 36} = 10 N$

θ is the angle made by R with the force of 8 N

$\Rightarrow θ = \tan^{- 1} (\frac{- 6}{8}) = - 36.87 ° = 37^{0} (A p p r o x .)$

The negative sign indicates that θ is in the clockwise direction with respect to the force of magnitude 8 N.

As per Newton’s second law of motion, the acceleration (a) of the body is given as:

F = ma

$\Rightarrow a = \frac{F}{m} = \frac{10}{5} = 2 m / s^{2}$