Spring 2015-2016 Prof. Dr. Ahmed Abdel-Naby, Dr. Mohamad Kanaan, Dr. Amr Ibrahim & Dr. Amine Moughlbay
Beirut Arab University
Department of Mechanical Engineering
MCHE 213 Assignment #2
[1]
The 300-kg bar B, originally at rest, is being towed over a series of small rollers. The
motor M is drawing in the cable for a short time at a rate of
m/s, where
seconds. Neglect the mass of the cable, pulley, and the rollers.
a) Determine the tension in the cable at
seconds.
b) How far does the bar move in 5 seconds?
Ans: T  1200 N ; s  16.67m
[2]
A 20-kg suitcase slides from rest 5 m down the smooth ramp.
a) Determine the point where it strikes the ground at C.
b) How long does it take to go from A to C?
Ans: R  1.53m; t AC  1.68s
[3]
The double inclined plane supports two blocks A and B, each having a weight of 10 lb. If the
coefficient of kinetic friction between the blocks and the plane is
, determine the
tension in the cord and the acceleration of block A.( g=3202ft/s2 )
Ans: T  7lb; a A  3.7 ft / s 2
Problem 4
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Spring 2015-2016 Prof. Dr. Ahmed Abdel-Naby, Dr. Mohamad Kanaan, Dr. Amr Ibrahim & Dr. Amine Moughlbay
[4]
The 125-kg concrete block A is released from rest in the position shown and pulls the 200 kg
log up the 30° ramp. If the coefficient of kinetic friction between the log and the ramp is 0.5,
determine:
a) the acceleration of block A,
b) the tension in the cable,
c) the velocity of block A just before it hits the ground at B.
2
Ans: a A  1.78 m/s  ;T  1004 N ; v A  4.62 m/s 
[5]
If blocks A and B of mass 10 kg and 6 kg, respectively, are placed on the inclined plane and
released, determine the force developed in the link. The coefficients of kinetic friction between
the blocks and the inclined plane are
and
Neglect the mass of the link.
Ans: F  6.37 N
[6]
The 10-lb suitcase slides down the curved ramp for which the coefficient of kinetic friction is
. If at the instant it reaches point A it has a speed of 5 ft/s, determine the normal force
on the suitcase and the rate of increase of its speed.
Ans:
T  5.89 lb ; a  23 ft/s2
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