What is the kinetic energy of a 2 kg object moving at 10 m/s?
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Correct Answer: D. 100 J
Explanation:
K=½mv².
K=½×2×100 = 100 J.
MCQ Collection
Pakistan MCQs
Practice Pakistan questions with answers and explanations.
What is a conservative force?
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Correct Answer: A. A force whose work depends only on initial and final positions
Explanation:
For conservative forces, work around a closed path is zero.
Gravity and ideal spring force are examples.
What is momentum?
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Correct Answer: B. Mass multiplied by velocity
Explanation:
Linear momentum is a vector quantity p=mv.
Its direction is the direction of velocity.
What is impulse?
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Correct Answer: C. Change in momentum
Explanation:
Impulse equals force integrated over time.
For constant force, J=FΔt=Δp.
When is linear momentum conserved?
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Correct Answer: D. When net external impulse is zero
Explanation:
Internal forces cancel in pairs within a system.
With no net external impulse, total momentum remains constant.
What is an elastic collision?
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Correct Answer: A. A collision conserving both momentum and kinetic energy
Explanation:
All isolated collisions conserve momentum.
Elastic collisions also conserve total kinetic energy.
What is a perfectly inelastic collision?
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Correct Answer: B. A collision in which objects stick together
Explanation:
The objects share a common final velocity.
Momentum is conserved, but kinetic energy is not.
What is torque?
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Correct Answer: C. The turning effect of a force about an axis
Explanation:
Torque depends on force, lever arm, and angle.
It is the rotational counterpart of force.
What is the moment arm?
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Correct Answer: D. Perpendicular distance from the axis to the force's line of action
Explanation:
Torque magnitude equals force times perpendicular lever arm.
A larger moment arm produces greater turning effect.
What is angular velocity?
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Correct Answer: A. Rate of change of angular displacement
Explanation:
Angular velocity describes how fast and in which sense an object rotates.
Its SI unit is rad/s.
A lift moves upward at constant velocity carrying a 60 kg person. Using g=10 m/s², what is the normal force on the person?
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Correct Answer: B. 600 N
Explanation:
Constant velocity means zero acceleration and zero net force.
The normal force therefore equals the person's weight, 600 N.
What is angular acceleration?
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Correct Answer: B. Rate of change of angular velocity
Explanation:
Angular acceleration measures how quickly rotational speed changes.
Its SI unit is rad/s².