Question

A body of mass 5 kg accelerates from 12 m/s to 20 m/s in 4 seconds due to the application of a force on it. Calculate the magnitude of this force (in N).
A) 40 B) 10 C) 20 D) 80

Answer 1

Solution :-

Given :-

• Mass ➡ 5 kg
• Initial Velocity (u) ➡ 12 m/s
• Final Velocity v ➡ 20 m/s
• Time (t) ➡ 4 s

To Find :-

• Magnitude of Force (F)

Formula Used :-

• $\underline{ \boxed{\huge \pink{ \sf F =M (\dfrac{v-u}{t})}}}$

We know F ➡ M × a

and a = v-u/t

So, F = M(v-u/t)

Therefore, Subsisting Values

$\sf \implies F = 5 (\dfrac{20-12}{4})$

$\sf \implies F = 5 ( \cancel{\dfrac{8}{4}})$

$\sf \implies F = 5 \times 2$

$\sf \implies F = 10$

Thus, 10 N is the Correct Answer

Hence, Solved ♡

Answer 2

Answer :-

Given :

• m = 5 kg
• u = 12 m/s
• v = 20 m/s
• t = 4 sec

To find :

Force - F

Formula used :

• F = ma
• v = u + at

Solution :-

For calculating force, we first need to find acceleration -

Calculating Acceleration :-

• u = 12 m/s
• v = 20 m/s
• t = 4 sec

Substituting the value in first equation of motion -

v = u + at

20 = 12 + 4a

8 = 4a

a = 8/4

a = 2m/s²

Calculating Force :-

• m = 5 kg
• a = 2 m/s²

Substituting the value in formula

F = ma

F = 5 × 2

F = 10 N