Practice Pakistan questions with answers and explanations.
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Total momentum is 3×4+1×2=14 kg·m/s.
Total mass is 4 kg, so v=3.5 m/s.
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Take initial velocity as +5 and final as -3.
|Δp|=|2(-3-5)|=16 kg·m/s.
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Torque is force times perpendicular distance.
τ=10×0.5 = 5 N·m.
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Torque is rF sinθ.
τ=2×20×sin30° = 20 N·m.
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Angular velocity is angular displacement divided by time.
ω=10/2 = 5 rad/s.
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Angular acceleration is change in angular velocity over time.
α=(16-4)/3 = 4 rad/s².
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Linear speed is v=rω.
V=0.5×8 = 4 m/s.
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Potential energy change is mgh.
5×10×8 = 400 J.
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Power is work divided by time.
P=600/3 = 200 W.
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Energy transferred is Pt.
1000×20 = 20,000 J.
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Use W=Fd cosθ.
W=10×4×cos60° = 20 J.
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Kinetic energy is ½mv².
K=½×4×9 = 18 J.
