Question

A force of 5N changes the velocity of a body from 10m/s to 20m/s in 5s. How much force is required to bring about the same change in 2s?

Answer 1

Force = Mass × Acceleration

Acceleration = (Change in Vel. / Time) = ((20-10)/5) = 2m/s^2

Therefore,
5 = Mass × 2
Mass = 2.5kg

To bring the same change in 2 secs,
Acceleration = ((20-10)/2) = 5m/s^2

Force = 2.5 × 5 = 12.5N

Answer 2

Answer: The answer is 12.5N

Force: Push or pull occurred on an object called the Force acting on the object. Its SI unit is Newton (N).

Explanation:

Step 1: Given Data

Initial force, $F_i = 5N$

Initial velocity, $v_i= 10ms^{-1}$

Final velocity, $v_f= 20ms^{-1}$

Initial timing, $t_i=5s$

Required timing, $t_r=2s$

Let required Force be F

Step 2: Find required Force F

Acceleration $a=\frac{v_f-v_i}{t_i}$

$a=\frac{20-10}{5}=\frac{10}{5}=2ms^{-2}$

Initial Force = mass X Acceleration

$mass = \frac{F_i}{a}\\mass = \frac{5}{2}= 2.5kg$

To bring the same changes in 2s

a $=\frac{20-10}{2}=5ms^{-2}$

Required Force F = mass X acceleration

$F = mXa\\F = 2.5 X 5\\F = 12.5N$