Forces and Moments

Question 1

What causes friction

Answer 1

It is caused by irregularities in surfaces in mutual contact and depends on surfaces in contact as well as how much they are pressed against each other. It is component of contact force along surface of contact

Question 2

Characteristics of viscous force

Answer 2

Magnitude of viscous force increases with increase in speed of object, also depends on shape, size, texture of surface and viscosity of fluid

Question 3

What happens to spring constant after spring has been stretched beyond elastic limit

Answer 3

Graph will shift along x-axis parallel to original F-x graph according to how much elastic limit has been exceeded

Question 4

Conditions for equilibrium

Answer 4

Resultant force on it must be zero in any direction
Resultant torque must be zero about any axis of rotation

Question 5

Property of system in equilibrium

Answer 5

Lines of action of non-parallel forces pass through a common point