Question

A body of mass 5kg is moving with a velocity of 10m/s. A force is applied to it so that in 25 seconds;it attains a velocity of 35m/s. Calculate the value of the force applied .

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Answer 1

Given:

• Mass of body = 5kg
• Velocity = 10 m/s
• A force is applied on the body so that the velocity becomes 35 m/s

To find:

• Force applied on the body

Solution:

Firstly finding acceleration of the body after the force applied

Then , here the

• Initial velocity = 10 m/s
• Final velocity = 35 m/s
• Time taken = 25s

Now , as we know that

a = v - u/t

Where

• a : acceleration = ?
• v : final velocity = 35 m/s
• u : initial velocity = 10m/s
• t : time taken = 25 s

Substituting the values we have

→ a = 35 - 10/25

→ a = 25/25

→ acceleration = 1 m/s²

Now , finding the force applied on the body

As we know that

F = m × a

Where

• F : force = ?
• m : mass = 5kg
• a : acceleration = 1 m/s²

Substituting the values we have

→ F = 5 × 1

→ F = 5 kgm/s² or N

Hence , the force applied on the body = 5N

Answer 2

Answer :

• 5 N

Given :

• Mass (m) = 5 kg
• Initial velocity (u) = 10 m/s
• Final velocity (v) = 35 m/s
• Time (t) = 25 s

To find :

• Force applied (F)

Solution :

The formula of force is given by :

$\boxed{\tt Force = Mass \times Acceleration}$

$\therefore$ , to find force , we must first find the acceleration produced in the body .

Using the first equation of motion ,

v = u + at

→ 35 = 10 + a (25)

→ 35 -10 = 25a

→ 25 = 25 a

→ a = 25/25

→ a = 1 m/s²

Now , the force applied to the body of 5 kg to produce an acceleration of 1 m/s² is :

F = ma

→ F = 5 × 1

→ F = 5 N

Therefore , the force applied is 5 N .

_____________________________

• An agent that causes change in state of a body or its shape or both is called force .
• It is a vector quantity .
• Its SI unit is Newton equivalent to 1 kgm/s² .
• Its CGS unit is dyne and 1 Newton = 10⁵ dyne .