1. What is the SI unit of force?
A. Joule
B. Newton
C. Pascal
D. Watt
Show Answer
Answer: B. NewtonExplanation: Force is measured in Newton (N).
2. An ideal machine is one whose efficiency is
A. 50%
B. <50%
C. >50%
D. 100%
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Answer: D. 100%Explanation: In ideal machine there is no loss of energy or no frictional loss. It converts the total input energy into output. (N).
3. The magnitude of frictional force depends upon
A. area
B. shape
C. nature of the contact surface
D. none of the above
Show Answer
Answer: C. 100%Explanation: Frictional force depends on the nature of the contact surface. Frictional force F= μR. So the magnitude of frictional force depends on co efficient of friction (μ) which refresents the nature of the surface.