Question

Question 28:
A body of mass 5 kg is moving with a velocity of 10 m/s. A force is applied to it so that in 25 seconds, it attains a velocity of 35 m/s. Calculate the value of the force applied.

Lakhmir Singh Physics Class 9

Answer 1

Mass =5kg
final velocity = 25 m/s
initial velocity = 10m/s
Time taken = 20sec
using first equation of motion
v = u+at
25 = 10+(a)(20). => 15 = 20a => a = 15/20 m/s² = 3/4 m/s²

we know that,
force = mass × acceleration
force = 5kg × 3/4 m/s² => 15/4 N = 3.75 N => force applied