Question

An object with a mass of 100Kg changes its velocity from 90 kmph to 72 kmph in 3
20 seconds. Calculate force acting on the object.​

Answer 1

Explanation:

90kmph=25mph, 72kmph=20mph

F=m×(dv/dt)

F=100×(20-25)/320

F=-500/320

F=25/16 N Backwards

Answer 2

The force acting on the object = 1.5625 N

• Force = mass * acceleration

          = mass * (change in velocity per second)

• Given ,  

Initial velocity = 90 Km/h = 25 m/s

Final velocity = 72 Km/h = 20 m/s

Time = 320 s

• Acceleration = (20 – 25) / 320

                       =  -0.015625 m/s2  

Force = 100 * ( -0.015625 m/s2 )

           = - 1.5625 N

• It is a retarding force of 1.5625 N