Kathmandu University
Department of Mechanical Engineering
MEEG 216-Engineering Mechanics
Class Practice 3 (Group work)
A body of mass 400 kg resting on rough horizontal plane is pulled by a force F applied to the body
making an angle 60° with the horizontal. The body attains a velocity of 100 m/s in 5 seconds. Taking µ =
0.2, find the value of F required.[13053.2 N]
The velocity of a truck weighing 100 kN changes its velocity from 40 km/hr to 60 km/hr in 10 seconds.
Determine the force exerted on the truck assuming the coefficient of friction between the road and truck
tyre is 0.3. [34.65 kN]
A vehicle of 4000 N weight is moving with a velocity of 90km/hr. A force of 200 N acts on it for 120
seconds. Find the velocity of the vehicle when (a) the force acts in the direction of vehicle motion and (b)
the force acts in the opposite direction of vehicle motion.[83.8 m/s, -33.8 m/s]
A driver of an automobile travelling along a high way applies brake to save the dog crossing the road. The
automobile stops within 2 seconds at a distance of 10 meters. Find the coefficient of friction between
the road and tyres if the car moved with constant deceleration. [0.51]
A truck of 30 kN weight running at 50 km/hr on a level road is brought to rest in 30 seconds by applying
the brakes to avoid an accident. Find the average force of resistance acting on the truck. [1416 N]
A tractive force of 200 kN is acting on an electric train whose weight is 8000 N. the friction resistance to
the motion of the train is 1% of its weight. Determine the time taken by the train to accelerate to a
speed of 96 km/hr from rest. [181.6 s]
A rectangular block 10 N is resting on a rough horizontal plane. This block is attached to another weight
of 8 N attached with a cord and hanging over a smooth pulley vertically. If the coefficient of friction of
the horizontal surface is 0.2, find (a) acceleration of the system. (b) tension in the cord and (c) force
acting on the pulley (d) if the system is released from rest, determine the time taken by the weight 8 N to
fall over the edge. The weight 10 N is 1.5 m away from the pulley. [3.27 m/s2, 5.33 N, 7.54 N, 0.96 s]
Two blocks A and B of masses 280 kg and 420 kg respectively are joined by an inextensible cable. The
body A is lying in a horizontal plane and body B is hanging freely. Assume that the pulley is frictionless
and coefficient of friction between block A and the surface is 0.3. The system is initially at rest.
Determine (a) acceleration of block A, (b) velocity after it has moved 3.5 m, and (c) velocity after 1.5
seconds. [4.7 m/s2, 7.06 m/s]
A body weighing 400 N is resting on a rough horizontal plane inclined at 20 degree to the horizontal. It is
pulled up the plane from rest by means of a light flexible rope running parallel to the plane and passing
over a light frictionless pulley at the top of the plane. The portion of rope beyond the pulley hangs
vertically and carries a weight 225 N at the end. If the coefficient of friction for the plane and the body is
0.15, find (a) tension in the rope, (b) acceleration of the body, (c) distance moved by the body in 3
seconds, starting from the rest.
Two rough inclined planes inclined at 30 degrees and 60 degrees to the horizontal and the same height
are placed back to back. Masses of 12 kg and 24 kg are placed on the faces and re connected by a string
passing over the pulley on the top of the planes. If coefficient of friction between all contact surfaces is
0.6, find the resulting acceleration and the tension in the string.