Mathematical Example: Newton 1st Law

Example 1: What is the force to be applied to a mass of 50 kg to produce an acceleration of 4 ms^-2 ?

Solution

Here,

mass of the body, m = 50 kg

acceleration, a = 4 ms^-2

force, F= ?

We know, F = ma          

=50 kg x 4ms^-2

= 200 kg ms^-2 = 200 N

Ans: 200 N

Example 2: A boy pushes a box of mass 20 kg with a force of 50 N. What will be the acceleration of the box?

Here,

mass of the box, m = 20 kg

applied force, F= 50 N

acceleration of the box, a = ?

We know

F = ma

a = F/ m = 50N/20kg = 2.5 ms^-2

Ans: 2.5 ms^-2