Engineering Mechanics
Assignment Sheet – 4
Kinematics of particles
Module - 4
1.A point is moving with uniform acceleration. In the 11th and 15 th second from the commencement, it
moves through 7.2m and 9.6 m respectively. Find its initial velocity and the acceleration with it moves.
May 2008 (5 marks).
Ans: U=0.9m/s, a=0.6m/s2
2. The velocity of a particle traveling in a straight line is given by v=6t-3t2 m/s. where t is in seconds. If
s=0 when t=0, determine the particles deceleration and position when t=3s. How far has the particle
travelled during the 3 second time interval and what is its average speed? Dec 2010 (5marks)
Ans: S=0, d=8m, s=2.67m/s
3. The car starts from rest and travels along a straight track such that it accelerates at a constants rate
for 10seconds and then decelerates at a constant rate. Draw the v-t and s-t graphs and determine the
time ‘t’needed to stop the car. How far has the car travelled? May 2009 (10 marks)
Ans: t 1 =60(s)
4. An object is projected so that it just clears two obstacles each 7.5m high which are situated 50m from
each other. If the time of passing between two obstacles is 2.5 seconds, calculate the complete range of
projection and initial velocity of projection.
May 2008 (10 marks)
Ans: α=40.78, U= 26.41m/s.
Engineering Mechanics
Assignment Sheet – 4
Kinematics of particles
Module - 4
5. Explain what tangential and normal acceleration is? A Particle is moving in X-Y plane and its position is
defined b r=[3/2t2]i+[2/3t3]j. Find radius of curvature when t=2 sec. Dec2007 [10 marks]
Ans:
R=41.67m
6. The motion of a particle is defined by the position vector, r=6ti+4t2j where ‘r’ is in meters and ‘t’ is in
seconds. At the instant when t=3 seconds, find (i) Tangential and Normal Components of accelerations
(ii) Radius of curvature. May 2011 (10 marks)
Ans: a T= 7.76m/s2,a N= 315.5m, ρ=315.5m
7. A Curvilinear motion of a particle is defined by vx= 25-8t m/s and y=48-3t2m. At t=0, x=0. Find out
position, velocity and acceleration at t=4sec.
May 2013 [4marks]