Question

Few men pushes a truck weighing 6 tonnes which is initially at rest on a horizontal track with a steady force of 300 N. The resistance to the motion amounts to 30 N per tonne. The velocity of the truck at the end of 20 seconds is

Answer 1

Given,
Initial velocity, u=0
Mass of truck, M=5ton=5000kg
Resistive force per unit ton, μ=60N/ton
Forward force, F
f
​
=400N
Resisting force, F
r
​
=μM=60×5=300N
F
net
​
=F
f
​
−F
r
​

Ma=400−300
a=
5000
100
​
=0.02ms
−2

Apply kinematic equation of motion
v=u+at
v=0.02×30=0.6ms
−1

Hence, velocity of truck after 30sec is 0.6ms
−2
.