Assignment -3
1. The coefficient of restitution for elastic bodies is
a) 1
b) 0 to 1 c) Less than one
d) Greater than one
2. If a particle starts from a point and then returns to same point, then the average speed
a) Zero b) not equal to zero c) constant d) Not constant
3. Two balls of equal mass and of perfectly elastic material are lying on the floor. One of the
ball with velocity v is made to struck the second ball. Both the balls after impact will
move with a velocity
a) v
b) v/2
c) v/4
d) v/8
4. The friction experienced by the body during rest is called as
a) static friction
b) dynamic friction c) sliding friction
d) rolling friction
5. The unit of angular acceleration is
a) N-m
b) m/s c) m/s2 d) rad/s2
6
. The capacity of doing the work is known as energy, the energy may be of
a) potential energy
b) kinetic energy c) strain energy d) all of the above
7. A redundant frame is also called __________ frame.
a) Perfect
b) Imperfect c) Deficient d) None of the above
8. 4.
The path described by the projectile is called as
a) Range
b) Height
c) Trajectory
d) Projectile
9. If two bodies having masses m1 and m2 (m1>m2) have equal kinetic energies, the
momentum of body having mass m1 is __________ the momentum of body having mass
m2.
a) Equal to
b) Less than
c) Greater than d) None of the above
10. The value of co-efficient of friction lies
a) less than 1
b) Greater than 1 c) depends on type of friction d) equal to 1
11. Define Range of a projectile.
12. State the principle of work and energy.
13. Analyse the motion of a particle thrown horizontally from a certain height?
14. Define the term Co-efficient of friction.
15. Define coefficient of restitution.
16. State the law of conservation of momentum.
17. Distinguish between Frame and Truss.
18. Differentiate between kinematics and kinetics.
19. Mention the different types of plane rigid body motion.
20. Classify the various types of truss.
21. A 500N block is in contact with a level plane, the coefficient of friction between two
contact surfaces being 0.25. if the block is acted upon by a horizontal force of 1300N, what
time will elapse before the block raches a velocity of 24m/s.
22. Two bodies one of which is 200N with a velocity of 10m/s and the other of 100N with a
velocity of 10m/s move towards each other and impinges centrally. Find (i) The velocity of
each body after impact (ii) The loss in kinetic energy due to impact. if the co-efficient of
restitution is 0.6.
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Assignment -3
23. A motor car is uniformly accelerated from 30km/hr to 45km/hr over a distance of 300m. if
the wheels are 1m diameter, find the angular acceleration of the wheels.
24. A stone is dropped from the top of a tower, 15m high. At the same time, an another stone is
thrown upwards from the foot of the tower. Both the stones meet at a height of 5m. Hence, find
the velocity with which the second stone is thrown upward?
25. Determine the forces in the members of the pin-jointed frame shown in figure by method of
joints.
26. Two blocks of weight 150N and 50N are connected by a string and passing over a frictionless
pulley as shown in fig. Find the acceleration of blocks A and B and the tension in the string.
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Assignment -3
27. A truss supported on an inclined plane at an angle of 30o with horizontal is shown in figure.
Determine the forces in all the members.
28. A motor A is travelling from west to east at a constant speed of 18km/hr. when the motor A
cross north-south road as shown in fig, a lorry B starts from rest, 40m north of the intersection
and moves with a constant acceleration of 2m/s2 . Find the position, velocity and acceleration of
lorry relative to motor A, 4 seconds after the observation.
29. Two blocks A and B of weight 100N and 200N respectively are initially at rest on a 30o
inclined plane as shown in figure. The distance between the blocks is 6m. The coefficient of
friction between the block A and the plane is 0.25 and that between the block B and the plane is
0.15. if they released at the same time, in what time the upper block B reaches block A.
30. A Bullet of mass 30g is moving horizontally with a velocity of 450m/s and strikes a wooden
block of weight 45N, resting on a rough horizontal floor. The bullet is embedded into the block
and then both block and bullet move as a single unit. Calculate the distance moved using (i)
D’Alembert’s principle (ii) Work- energy method. Take: µ=0.45.
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Assignment -3
31. Two bodies one of mass 30kg, moves with a velocity of 9m/s strikes on an another body of
mass 15kg, moving in the opposite direction with the velocity of 9m/s centrally. Find the
velocity of each body after impact, if the coefficient of restitution is 0.8
32. Determine the forces in the members of the frame shown in fig by method of joints.
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