3.2

Question 1

Resultant force

Answer 1

Single force that is the sum of all the forces acting on a body

Question 2

A Newton

Answer 2

Force that causes a mass of 1kg to accelerate at 1ms^-2

Question 3

Measuring terminal velocity PAG

Answer 3

Tube filled with liquid, elastic bands at intervals.
Drop ball bearing into liquid and start timer.
Record time taken to reach each elastic band marker. (Measure distance from top to each band)
Repeat experiment (magnet to remove ball) recording time taken to go each distance.
Calculate velocity for each time period, plot against time: identify terminal velocity from curve

Question 4

Equilibrium

Answer 4

State of objects when all force in the same plane are balanced: zero net force

Question 5

Moment of force

Answer 5

Product of a force and the perpendicular distance to its line of action from a point

Question 6

Principle of moments

Answer 6

For an object to be in rotational equilibrium, the sum of the clockwise moments must be equal to the sum if the anti clockwise moments

Question 7

Torque

Answer 7

Turning moment due to a couple, the product of one of the forces and the perpendicular distance between them

Question 8

Center of mass

Answer 8

Single point at which all the mass of the object can be assumed to be situated

Question 9

Centre of gravity

Answer 9

The single point through which the entire weight of the object can be assumed to act through

Question 10

Centre of mass/gravity PAG

Answer 10

Make three holes in random places at the edge of the shape.
Hang the shape from each hole and attach a plum line to the point the shape is hung from and note this vertical line on the shape.
Each time the shape is hung the new line should intersect the other lines at a common point- the centre of mass/gravity

Question 11

Density

Answer 11

Mass per unit volume

Question 12

Archimedes’ principle

Answer 12

The upward buoyant force exerted on an object immersed in a fluid is proportional to the weight of fluid that object displaces