Question

A force acting for 5 seconds on a body of mass 2.0 kg initially at the rest force is there withdrawn and the body moves with a velocity of 2 metre per second minus find the magnitude of force
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Answer 1

Given :

• Time of applied force = 5 s

• Mass of the body = 2 kg

• Final Velocity of the body = 2 m/s

• Initial velocity of the body = 0 m/s

To find :

The magnitude of force appled.

Solution :

We know that Force is the product of the Mass and the Acceleration .

So, to find force we need both the mass and acceleration.

To find the Acceleration :-

Using the First Equation of motion and substituting the values in it , we get :

$\boxed{:\implies \bf{v = u + at}}$

Where :-

• v = Final Velocity
• u = Initial Velocity
• a = Acceleration
• t = Time Taken

$:\implies \bf{ = u + at}$

$:\implies \bf{2 = 0 + a \times 5}$

$:\implies \bf{2 = 5a}$

$:\implies \bf{\dfrac{2}{5} = a}$

$:\implies \bf{0.4 = a}$

$\boxed{\therefore \bf{Acceleration\:(a) = 0.4\:ms^{-2}}}$

Hence, the acceleration of the body is 0.4 m/s².

Now ,

To find the Force :-

Using the formula for force and substituting the values in it, we get :

$\boxed{:\implies \bf{F = ma}} \\ \\ \\ :\implies \bf{F = 2 \times 0.4} \\ \\ \\ :\implies \bf{F = 0.8} \\ \\ \\ \boxed{\therefore \bf{Force\:(F) = 0.8\:N}}$

Hence, the magnitude of force is 0.8 N.