Question

A body of mass 20kg is initially at rest. A force of 10N is applied to the body. Find the velocity of body after 15sec.
( Give step by Step answer)​

Answer 1

Answer :

• Final velocity of body = 7.5 m/s

Given:

• Mass of body, m = 20 kg
• Initial velocity of body, u = 0 m/s
• Magnitude of force applied on body, F = 10 N
• time for which force is applied, t = 15 sec

To find :

• Final velocity of body after 15 seconds, v = ?

Formulae required :

• Newton's second Law

        F = m a

• First equation of motion

       v = u + a t

[ where F is force applied, a is acceleration, m is mass of body, v is final velocity, u is initial velocity and t is time ]

Solution :

Using Newton's second Law

→ F = m a

→ 10 = ( 20 ) a

→ a = 10 / 20

→ a = 0.5 m/s²

Now,

Using first equation of motion

→ v = u + a t

→ v = ( 0 ) + ( 0.5 ) ( 15 )

→ v = 7.5 m/s

Therefore,

• Final velocity of body will be 7.5 m/s .

Answer 2

Explanation:

Given that a body of mass 20kg is initially at rest. A force of 10N is applied to the body.

We have to find the velocity of body after 15sec.

Force is defined as the product of mass and acceleration.

Force = mass × acceleration or F = ma

Also, acceleration is defined as the ratio of change in velocity with respect to time taken.

Acceleration = (Final velocity - Initial velocity)/Time or a = (v - u)/t

So,

F = m × (v - u)/t

Substitute the known values,

→ 10 = 20 × (v - 0)/15

→ 1/2 = (v - 0)/15

→ 15/2 = v

→ 7.5 = v

Hence, the final velocity of the body is 7.5 m/s.