4.1 Turning effects of forces

4 of 4 objectives have lessons · 0 studied · 0 secure

Lessons

Moments: why door handles live far from the hingeThe moment of a force is the force times the perpendicular distance from the pivot to its line of action, measured in N m. 5 min, not started
Centre of gravity: where all the weight seems to actAn object's weight can be treated as one force acting at a single point, its centre of gravity; for a uniform, symmetrical object that's its geometric centre. 5 min, not started
Moments of forces at an angleWhen a force isn't at right angles to the lever, multiply it by the perpendicular distance to its line of action, or use only its perpendicular component. 5 min, not started
Couples: pure spin, no shoveA couple is a pair of equal, opposite, parallel forces whose lines of action are separated; the resultant force is zero, so its only effect is rotation. 4 min, not started
The torque of a coupleThe torque of a couple is one of the forces times the perpendicular distance between their lines of action, and it's the same about every point. 5 min, not started

4 objectives

What Cambridge says you should be able to do, in our words. Codes are the topic number plus the objective’s position.

4.1.1

Understand that an object’s weight may be treated as acting at one point, its centre of gravity.

Taught in: Centre of gravity: where all the weight seems to act · 4 questions

4.1.2

Define the moment of a force and apply the definition.

Taught in: Moments of forces at an angle, Moments: why door handles live far from the hinge · 11 questions

4.1.3

Understand that a couple is a pair of forces whose only effect is to produce rotation.

Taught in: Couples: pure spin, no shove · 5 questions

4.1.4

Define the torque of a couple and apply the definition.

Taught in: The torque of a couple · 6 questions