Question

find the force applied on the body , if velocity of a body of mass 3kg chages from 2m/s to 20m/s in 9 seconds​

Answer 1

Given :

• Mass, m = 3 kg

• Initial Velocity, u = 2 m/s

• Final Velocity, v = 20 m/s

• Time, t = 9 seconds

To Find :

• The force applied on the body

Solution :

We will find the force using Newton's 2nd Law of motion which gives us the formula :

★ Force = Mass × Acceleration

Here, we're having the value of mass, let's find acceleration.

From 1st equation of motion :

★ v = u + at

→ 20 = 2 + (a)(9)

→ 20 = 2 + 9a

→ 20 - 2 = 9a

→ 9a = 18

→ a = 2 m/s²

Now, put the value of acceleration in the formula :

★ Force = Mass × Acceleration

→ F = 3 × 2

→ 6 Newtons

$\therefore$ The force applied on the body is 6 Newtons.

Answer 2

Answer :

We know the first equation of the motion.

➺ v = u + at (Where v = 20 m/s, u = 2 m/s, t = 9 seconds)

__________________[Putting Values]

➢ 20 = 2 + a(9)

➢ 20 - 2 = 9a

➢ 9a = 18

➢ a = 18/9

➢ a = 2

∴ Acceleration is 2 m/s²

$\rule{200}{2}$

Now, We know the formula to find force.

➺ Force = Mass * Acceleration

➢ Force = 3 * 2

➢ Force = 6

∴ Force applied on the body is 6N.