physics: Forces - vectors and moments

Question 1

resultant force

Answer 1

the single force that has the same effect as all of the forces acting on an object

Question 2

triangle of forces

Answer 2

a closed triangle drawn for an object in equilibrium. The sides of the triangle represent the forces in both magnitude and direction.

Question 3

components of a vector

Answer 3

the magnitudes of a vector quantity in two perpendicular directions

Question 4

resolving the vector

Answer 4

to split a vector into two vectors at right at right angles

Question 5

free body force diagram

Answer 5

a diagram showing all the forces acting on an object (but not the forces it exerts in other objects)

Question 6

centre of gravity

Answer 6

the point where the entire weight of an object appears to act

Question 7

moment of a force

Answer 7

the moment of a force about a point is the product of the force and perpendicular distance from the line of action of the force to the point.

Question 8

principle of moments

Answer 8

the sum of the colckwise moments about a pint is equal to the sum of the anticlockwise moments about the same point provided the body is in equilibrium

Question 9

couple

Answer 9

a pair of equal and opposite forces hat act on an object at different points and produce rotation only

Question 10

torque of couple

Answer 10

the product of one of the forces and the perpendicular distance between the forces