Forces

Question 1

Field of force

Answer 1

a region of space where a particle experiences a force

Question 2

Translational equilibrium

Answer 2

A body is in translational equilibrium when there is no resultant force

Question 3

Hooke’s Law

Answer 3

the change in length of a material is directly proportional to the force applied on it, provided that the limit of proportionality is not exceeded
F=kx

Question 4

Pressure

Answer 4

The force per unit area
p=F/A

Question 5

Rotational equilibrium

Answer 5

A body is in rotational equilibrium when there is no resultant torque about any point

Question 6

Principle of moments

Answer 6

For a body in rotational equilibrium, sum of clockwise moments about any point is equal to sum of anti-clockwise moment about the same point

Question 7

Moment of a force about a point

Answer 7

Product of the force and the perpendicular distance of the force to the pivot
M=Fd

Question 8

Torque of a couple

Answer 8

product of one of the forces and the perpendicular distance between the forces
torque=Fxd(perpendicular)

Question 9

centre of gravity

Answer 9

the point from where all the weight of a body seems to act

Question 10

viscous force

Answer 10

magnitude of viscous force on a body increases with the relative speed of the body with respect to the fluid

Question 11

equilibrium

Answer 11

there is no resultant force and there is no resultant torque about any point on it

Question 12

upthrust

Answer 12

the upward force exerted by a fluid on an object submerged fully or partially in the fluid due to the difference in pressure exerted by the fluid on the upper and lower surfaces of the object.
it acts through the centre of mass of the displaced fluid and is equal in magnitude and opposite in direction to the weight of fluid displaced by the body