University of Mines and Technology
Basic Mechanics MR/EL/ES 167
Assignment #3 [70 Marks]
Submission Date: Monday March 22 2021 10am via VLE
Question 1
Two forces P and Q are applied to an aircraft connection as shown in Fig Q12. The connection
is in equilibrium and that P = 600 N and Q = 780 N.
Figure Q12
i.
The magnitude of 𝐹𝐵 is
ii.
The unit vector for the force exerted on the rod A
iii.
The rectangular components of 𝐹𝐴 in Newtons
Question 2
A wooden block of mass 6 kg resting on a horizontal plane is pulled by force Q inclined 30o
to the horizontal with respect to the positive x-axis.
i.
ii.
iii.
iv.
Page 1 of 3
Draw a free body diagram for the block
What is the minimum value of Q required to start sliding if μk=0.3 and μs=0.35.
Determine the value of maximum friction between the pair of surfaces
Determine the value of kinetic friction
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Question 3
The structure shown supports part of the roof of a small building. Knowing that the tension in
the cable is 200 kN, determine the reactions at the fixed end E.
[10
marks]
Question 4
Two crates, each of mass 350 kg, are placed as shown in the bed of a1800-kg pickup truck. If
the truck is a front wheel drive.
i.
Draw a free body diagram for the truck
ii.
Determine the reactions at each of the two (a) rear wheels A, (b) front wheels B.
Question 5
Determine the reactions at A and B when h = 100 mm.
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Question5
The gravitational acceleration at sea level is 9.81 m/s2. At what altitude h, will a body weigh
half of its weight at sea level? [Radius of earth Re = 6371 km].
A. 2𝑅𝑒
B. 1 + 𝑅𝑒 /√2
C. 𝑅𝑒 (√2 − 1)
D. 𝑅𝑒 (1 + √2)
E. 𝑅𝑒 /2
Question6
An astronaut weighs 720 N on earth at sea level. Determine his mass on moon. [Given that the
moon has a mass of 7.35 x 1022 kg and an average diameter of 3474.2 km]
Question 7
Find the tension/compression in members CE, DE.
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