Question

how much force is required to change the velocity of an object of mass 20 kg from 10m/s to 20 m/s in 4s

Answer 1

Given:-

• Mass ,m = 20kg
• Initial velocity ,u = 10m/s
• Final velocity, v = 20m/s
• Time taken ,t = 4s

To Find:-

• Force ,F

Solution:-

According to the Question

Firstly we calculate the acceleration of the object . Rate of change in velocity is called acceleration.

• a = v-u/t

where,

• v is the final velocity
• a is the acceleration
• u is the initial velocity
• t is the time taken

Substitute the value we get

$:\implies$ a = 20-10/4

$:\implies$ a = 10/4

$:\implies$ a = 2.5 m/s²

• So the acceleration is 2.5m/S²

Now, calculating the Force . Force is defined as the product of mass & acceleration.

• F = ma

where,

• F denote Force
• m denote mass
• a denote acceleration

substitute the value we get

$:\implies$ F = 20×2.5

$:\implies$ F = 2×25

$:\implies$ F = 50 N

• Hence, the force required to change the velocity is 50 Newton.

Answer 2

Given :-

Velocity of an object of mass 20 kg from 10m/s to 20 m/s in 4s

To Find :-

Force

Solution :-

Force = Mass × Acceleration

Force = m × (v - u/t)

F = 20 × (20 - 10/4)

F = 20 × (10/4)

F = 20 × 2.5

F = 50

Hence

Force in 50 N