Madda Walabu University
College of Engineering
Mechanical Engineering Department
Assignment of Engineering Mechanics II (Dynamics) for Civil Engineering 2 nd year
Extension students
► Submission Date: 21/12/2014 E.C
1. The velocity of a particle is given by 𝒗 = 𝟐𝟎𝒕𝟐 − 𝟏𝟎𝟎𝒕 + 𝟓𝟎, where 𝒗 is in meters per second and
t is in seconds. Plot the velocity 𝒗 and acceleration a versus time for the first 6 seconds of motion
and evaluate the velocity when a is zero.
2. The acceleration of a particle is given 𝒂 = 𝟒𝟎𝒕 − 𝟑𝟎, where 𝒂 is in meters per second squared and
𝒕 is in seconds. Determine the velocity and displacement as functions of time. The initial
displacement at t=0 is so= -5m, and the initial velocity VO=3m/s.
3. The velocity of a particle along the s-axis is given by 𝒗 = 𝟓𝒔𝟑/𝟐 , where s is in millimeters per
second. Determine the acceleration when s is 2 millimeters.
4. The motion of a particle is defined by the relation 𝒙 = 𝟔𝒕𝟒 − 𝟐𝒕𝟑 − 𝟏𝟐𝒕𝟐 + 𝟑𝒕 + 𝟑, where x and
t are expressed in meters and seconds, respectively. Determine time, position and the velocity when
a=0.
5. An elevator is moving upward at a constant speed of 4 m/s. A man standing 10 m above the top of
the elevator throws a ball upward with a speed of 3 m/s. Determine (a) when the ball will hit the
elevator, (b) where the ball will hit the elevator with respect to the location of the man .
Figure for question number 5.
Prepared By: Habtamu Mitiku (MSc, Assistant Professor in CIM)