Question 11 Mark
For most of the surfaces used in daily life, the friction coefficient is less than 1. Is it always necessary that the friction coefficient is less than 1?
Answer
View full question & answer→No.
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Question 21 Mark
What is the average friction force when a person has a usual 1km walk?
Answer
View full question & answer→Zero.
As $<\vec{\text{a}}>=\frac{\vec{\text{v}}_{\text{f}}-\vec{\text{v}}_{\text{i}}}{\text{t}}=\vec{\text{0}}$ as men starts with zero velocity and ends with zero velocity.
As $<\vec{\text{a}}>=\frac{\vec{\text{v}}_{\text{f}}-\vec{\text{v}}_{\text{i}}}{\text{t}}=\vec{\text{0}}$ as men starts with zero velocity and ends with zero velocity.
Question 31 Mark
Why is it easier to push a heavy block from behind than to press it on the top and push?
Answer
View full question & answer→Pressing increase the normal reaction, thus increasing the friction.
Question 41 Mark
Can a tug of war be ever won on a frictionless surface?
Answer
View full question & answer→No, because on both team tension will be same and as there is no friction so one will win.
Question 51 Mark
Can you accelerate a car on a frictionless horizontal road by putting more petrol in the engine? Can you stop a car going on a frictionless horizontal road by applying brakes?
Answer
View full question & answer→No, since road is frictionless, car wont move.
Question 61 Mark
Why is it difficult to walk on solid ice?
Answer
View full question & answer→Friction coefficient is very less so he can slip on surface.