Resolving moments

Question 1

State two conditions that must be satisfied for the rod to be in equilibrium.

Answer 1

resultant force zero

resultant torque about any point zero

Question 2

State two vector quantities.

Answer 2

acceleration, force,velocity

Question 3

state two scalar quantities

Answer 3

speed, distance,mass

Question 4

State the difference between a scalar quantity and a vector quantity.

Answer 4

vector has direction and a scalar does no

Question 5

Explain what is meant by centre of gravity.

Answer 5

the point at which the mass is thought to be concentrated

Question 6

Define the moment of a force.

Answer 6

product of the force and the perpendicular distance (1)

reference to a point/pivot

Question 7

State the Principle of Moments.

Answer 7

sum of) clockwise moments (about a point) =(sum of) anticlockwise
moments (1)
(for a system) in equilibrium

Question 8

Describe and explain one feature of the crane that prevents it from toppling over
when it is lifting a container.

Answer 8

The counterweight provides a (sufficiently large) anticlockwise moment to prevent the crane toppling clockwise