Question

a force acts for 0.2 sec on an object having mass 1.4kg initially at rest the force stops to act but the object moves through 4m in the next 2 seconds find the magnitude of the force

Answer 1

Hey there !

Solution :

Initial Velocity = 0 m / s

Final Velocity = ?

Final Velocity can be calculated by Displacement by time formula. Even though force has stopped, the object continues to move 4 m in 2 seconds.

Hence Velocity = 4 m / 2 s = 2 m / s

Hence Final Velocity = 2 m / s

Force = Mass * Acceleration

Acceleration = Rate of change of Velocity  i.e.

Acceleration = Final Velocity - Initial Velocity / Time

=> Acceleration = 2 m / s - 0 m / s / 0.2

=> Acceleration = 2 / 0.2 = 20 / 2 = 10 m / s²

Hence Acceleration = 10 m / s²

Force = Mass * Acceleration

Substituting in the formula we get,

Force = 1.4 kg * 10 m / s

Force = 14 kg.m / s or 14 N

Hence Magnitude of Force = 14 N

Hope my answer helped :-)

Answer 2

heya...

Here is your answer...