Anjuman-I-Islam’s
M. H. Saboo Siddik College of Engineering
8, Saboo Siddik polytechnic rd, Byculla, Mumbai
400008
First Year
Engineering Mechanics Question
set
4. Friction
Q.1For the following cases find force P needed to just impend the motion of the block Take weight of block to be
100 N and coefficient of static friction at the contact surface to be.0.4
Q.2. What should be the value of angle θso that the
motion of block A impend down the plane?
Coefficient of friction at all surface 1/3 Mass of
A =40 Kg Mass of B =13.5 Kg
Q.3.Find minimum Value of F to move block A up the
Plane µ=0.2 for all surfaces.
Q.4. Determine the weight W to Prevent downward
motion of the 1000 N body. Take
µ= 0.2 between the rope and the fixed drum and µ=0.3
for other surface of contact.
Q.5.Determine the force P to cause motion to impend.
Take masses of blocks A and B as 9 Kg respectively.
Coefficient of Sliding friction as 0.25 and that between
rope and pulley is 0.2. The force P and rope are parallel to
the inclined plane.
Q.6. Block A weighing 200 N is connected to block B of
weight W by a passing over rough pulley. Find Value of W
for which the motion just impends. Coefficient of friction
for all surfaces is 0.2.
Q.7. Determine the minimum Value and the direction of
the force P required causing motion of a 100 Kg block to
impend upon a 30º plane. Take µ=0.2
Q.8.A support block is acted upon by two forces as shown
in Figure Knowing that ㎲=0.35 and µk=0.25.Determine
the force P required.
(1)To start the block moving up the plane.
(2) To keep it moving up.
(3) to prevent it from sliding down.
Q.9.Two block A=100N, B=150 N are placed as shown in
Figure µ=0.1 between ground and block B and between
two block is 0.3.Find the minimum value of weight P in
the pan so that motion starts. Find whether B is stationary
w.r.t. A.
Q.10.A 10 Kg block is attached to link AB and rests on a
conveyor belt which is moving to the as shown in Figure.
The Coefficient of friction between the block and the belt
are ㎲=0.3 and µk=0.25 Determine:
(1) The force in link AB
(2) The horizontal force which be applied to the belt to
maintain its motion.
Q.11.Two inclined planes AC and BC inclined at 60ºand
30ºto the horizontal meet ridge C.A mass of100Kg rests
on inclined plane BC and is tied to a rope which passes
over a smooth pulley at the ridge. The other end of the
rope being connected to a block of W kg resting on plane
AC./Determine least and greatest value of W for the
equilibrium of the whole system.
Q.12.Two identical blocks A and B are connected by rod,
rest against vertical and horizontal planes respectively its
shown in Figure sliding impends when θ=45º,determine
the coefficient of friction µ.assuming it to be same of both
surfaces.
Q.13. A thin hoop of radius 1 m and weight 500 N rests
on an rough incline. What minimum coefficient of friction
is needed for this configuration? what is tension in the
wire. which is paralleled to incline.
Q.14. A homogeneous ladder as shown in Figure rests
against a smooth wall at A and a rough horizontal floor
the mass of ladder is 30 kg and is concentrated at 2 m
from bottom µ=0.35 at floor. will the ladder stand in 60®
position as shown ?
Q.15. A weightless ladder of length 8 m is resting against a
smooth vertical wall and rough horizontal ground as
shown The coefficient of friction between the ground and
the ladder is 0.25 .A man of weight 500 N wants to climb
up the ladder .Find how much distance along the ladder
the man can climb without slip. A second person weighing
800 N wants to climb up the same ladder. Would be climb
less than the earlier person? Find his distance covered.
Q.16.A ladder of length 7 m beam against a wall as shown
in Figure Assuming that the coefficient of static friction µs
at A for which equilibrium is maintained.
Q.17.A uniform ladder 3 m long weight 200 N. it is placed
against a wall 60® with flour as shown in Figure coefficient
of friction between the wall and the ladder is 0.3 and that
between the floor and the ladder is 0.4 .The ladder in
addition to its own weight has to support a man weighing
800 N at its top at A.
(1) Calculate the horizontal force F to be applied to the
floor level to prevent slipping.
(2) if the force F is not applied. What would be the
minimum inclination of the ladder with the horizontal so
that there is no slipping of it with the man at the top?
Q.18.A 100 N uniform rod AB is held in position as shown
in Figure if µ=0.15 at A and B calculate range of value of P
for which equilibrium maintained.
Q.19.A block A support a load W=5000 N and is be raised
by forcing the wedge B under it. The angle of friction for
all surfaces in contact is ø=15 Determine the force P.
which is necessary to start the wedge under the block.
The block and wedge have negligible weight.
Q.20.A block A weighing 40 KN is placed on another block
B weighing 10 KN shown in Figure .If ф=16.Find the force
P applied to the lower block B so as just start the upward
motion of block A.
Q.21. calculate the magnitude of the horizontal force P
acting on the wedges B and c to raise a load of 100 KN.
Resting on A. Assume µ=0.25 between wedges and
ground µ=0.2 between wedges and A. Also assume
symmetry of loading and neglect the weight of A,B and C.
Wedges are resting on horizontal surface and their slope
is 1:10.
Q.22.A block of mass 150 Jg is raised by a 10® wedge
weighing 50 Kg under it and by applying a horizontal force
at it as shown in Figure P.If and by
Q.20.Refering to given Figure µ=0.25 at floor,µ=0.3 at
wall and µ=0.2 between the blocks. Find
minimum value of horizontal force P applied to
the lower to the block that will hold the system
in equilibrium.
