Engineering Mechanics
JKSSB Junior Engineer (Mechanical) · Engineering Mechanics and Strength of Materials · 33 practice questions with answers and explanations: 12 Easy, 20 Medium, 1 Hard.
Sample questions
Sample Easy question 1
One horsepower is about:
- 1,000 watts
- 9.81 watts
- 100 watts
- 746 watts
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Answer: D. 1 HP = 746 W.
Sample Easy question 2
Impulse of a force equals the change in:
- Momentum
- Kinetic energy
- Potential energy
- Velocity only
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Answer: A. Impulse is force times the time it acts.
Sample Easy question 3
A body falls freely from rest. Its velocity after 3 seconds (g = 10 m/s²) is:
- 30 m/s
- 60 m/s
- 15 m/s
- 3.3 m/s
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Answer: A. v = g t = 10 × 3 = 30 m/s.
Sample Medium question 4
A ladder rests against a smooth vertical wall and a rough floor with coefficient of friction μ. It is on the point of slipping when the angle θ with the floor satisfies:
- tan θ = μ / 2
- tan θ = 1 / (2 μ)
- tan θ = 1 / μ
- tan θ = 2 μ
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Answer: B. Taking moments for a uniform ladder at limiting equilibrium gives tan θ = 1/(2μ).
Sample Medium question 5
Lami's theorem applies to:
- Two parallel forces
- Three concurrent forces in equilibrium
- A couple
- Any number of non-concurrent forces
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Answer: B. Each force is proportional to the sine of the angle between the other two.
Sample Medium question 6
The angle of friction φ is related to the coefficient of friction μ by:
- sin φ = μ
- cos φ = μ
- tan φ = μ
- φ = μ
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Answer: C. μ = F/N is the tangent of the angle of friction.
Sample Hard question 7
The centre of gravity of a semicircular lamina of radius R lies from its diameter at:
- R / π
- 2R / 3
- 4R / 3π
- R / 2
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Answer: C. It lies on the axis of symmetry.