# UNIT --1

```NRI INSTITUTE OF TECHNOLOGY
MECHANICAL ENGINEERING
ENGINEERING MECHANICS
ASSIGNMENT QUESTIONS
DEPARTMENT MECHANICAL ENGINEERING
UNIT --1
1. (a) Two forces equal to 2P and P respectively act on a particle. If first be doubled and the second
increased by 12N the direction of the resultant is unaltered, find the value of ‘P’?
(b) Define free body diagram, transmissibility of a force and resultant of a force?
2. (a) Explain various force systems with neat sketches?
(b) Two forces are acting at a point O as shown in fig. Determine the resultant in magnitude and
direction of the force.
3. A particle is acted upon by forces equal to P, 2P, 5P and 4P. The angle between the first and second,
the second and third and the third and fourth are 60, 90, 150 degrees respectively. Find the magnitude
and direction of the resultant force. The first force is on horizontal.
4. Four parallel forces are as shown in fig. Determine the magnitude of the resultant force and position of
the resultant force from point A.
5. (a) Three forces are acting at a point A(4,6,-4). If B( 3,6,2) is a point on the line of action of force P1
=40 KN, C(-3,4,-5) is the point on the line of action of the force P2 =50 KN and D(-5,-6,8) is the point
on the third force P3= 60KN, Determine the resultant of the three forces.
(b) State and explain the fundamental Laws of Mechanics?
6. A 675 N man stands on the middle rung of a 225 N ladder, as shown in Fig. Assuming a smooth
wall at B and a stop at A to prevent slipping, find the reactions at A and B?
Asso. Professor
NRI INSTITUTE OF TECHNOLOGY
MECHANICAL ENGINEERING
7.A roller of radius r = 0.3 m. and weight Q = 2000 N is to be pulled over a curb of height h = 0.15 m. by
a horizontal force P applied to the end of a string wound around the circumference of the roller (Ref.
Fig.). Find the magnitude of P required to start the roller over the curb.
8. Find the reactions Ra and Rb induced at the supports A and B of the right-angle bar ACB supported
as shown in Fig., and subjected to a vertical load P applied at the mid-point of AC.
9.A ball of weight Q = 12 N rests in a right-angled trough, as shown in figure. Determine the forces
exerted on the sides of the trough at D and E if all surfaces
are perfectly smooth.
10. A mast AB supported by a spherical socket at A and horizontal guy wires BC and BD carries a
vertical load P at B as shown in the figure below. Find the axial force induced in each of the three
members of this system.