P3.2 - Everything in the Specification

[blank_start]MOMENT[blank_end] - The turning [blank_start]effect[blank_end] of a force

If an object is not turning, the total clockwise moment and total anticlockwise moment must balance exactly about a pivot.

How do simple levers work?

Fill in the names of the three force multipliers below. Sc[blank_start]issors[blank_end], Whe[blank_start]elbarrows[blank_end], Ba[blank_start]rs[blank_end]

If the [blank_start]line[blank_end] of [blank_start]action[blank_end] of the [blank_start]weight[blank_end] of an object is [blank_start]outside[blank_end] the [blank_start]base[blank_end], there will be a [blank_start]resultant[blank_end] [blank_start]moment[blank_end], which will tend to cause the object to [blank_start]topple[blank_end].

[blank_start]CENTRE OF MASS[blank_end] - The [blank_start]point[blank_end] at which the [blank_start]mass[blank_end] of an object appears to act from.

Fill in the blanks to show how the centre of mass of any flat shape can be found: 1. Suspend the [blank_start]shape[blank_end] and a [blank_start]plumb[blank_end] line from the same [blank_start]point[blank_end]. 2. Draw a [blank_start]line[blank_end] along the [blank_start]plumb[blank_end] line. 3. Draw another [blank_start]line[blank_end] but suspend the [blank_start]shape[blank_end] from a different pivot [blank_start]point[blank_end]. 4. The [blank_start]centre[blank_end] of [blank_start]mass[blank_end] is where the two lines [blank_start]cross[blank_end].

The centre of mass hangs directly above the point of suspension.

Where is the centre of mass of a symmetrical object?

To get the maximum moment, you need to push at a right angle to the object.

Liquids are [blank_start]virtually[blank_end] [blank_start]incompressible[blank_end] - this means that their volume and [blank_start]density[blank_end] stay the same. In addition, [blank_start]pressure[blank_end] in a liquid is transmitted [blank_start]equally[blank_end] in all [blank_start]directions[blank_end].

A force applied to one point in a liquid will...

Hydraulic [blank_start]systems[blank_end] are used as force [blank_start]multipliers[blank_end] - they use a [blank_start]small[blank_end] force to produce a [blank_start]large[blank_end] force. This is done through the [blank_start]cross-sectional[blank_end] areas of the pistons in a simple hydraulic [blank_start]system[blank_end]. One piston has a [blank_start]smaller[blank_end] cross-sectional area than the other, and because [blank_start]pressure[blank_end] is transmitted [blank_start]equally[blank_end] in all [blank_start]directions[blank_end], the pressure at both pistons is [blank_start]the same[blank_end]. Pressure is equal to force [blank_start]divided by[blank_end] area; therefore, at the [blank_start]first[blank_end] piston, a pressure is exerted on the liquid using a small force. This pressure is [blank_start]transmitted[blank_end] to the second piston. Force is equal to pressure [blank_start]multiplied by[blank_end] area, and because the [blank_start]second[blank_end] piston has a larger area, there will be a larger force produced.

Complete the blanks to give three uses of hydraulic systems. He[blank_start]avy[blank_end] ma[blank_start]chinery[blank_end], in[blank_start]dustrial[blank_end] ja[blank_start]cks[blank_end], ca[blank_start]r[blank_end] br[blank_start]aking[blank_end] sy[blank_start]stems[blank_end].

[blank_start]CENTRIPETAL[blank_end] FORCE - The force directed towards the [blank_start]centre[blank_end] of the [blank_start]circle[blank_end] by an [blank_start]object[blank_end] moving in a [blank_start]circle[blank_end].

The unit of pressure is newton-metres squared.

Fill in the blanks to explain the process of circular motion: 1. [blank_start]Velocity is both[blank_end] [blank_start]the speed and direction[blank_end] [blank_start]of an object[blank_end]. 2. [blank_start]If an object[blank_end] [blank_start]is travelling[blank_end] [blank_start]in a circle[blank_end] [blank_start]it is constantly changing direction[blank_end]. 3. [blank_start]This means that[blank_end] [blank_start]its velocity[blank_end] [blank_start]is constantly changing[blank_end]. 4. [blank_start]This means that the object[blank_end] [blank_start]is accelerating[blank_end] [blank_start]towards the centre[blank_end] [blank_start]of the circle[blank_end]. 5. [blank_start]There must be[blank_end] [blank_start]a resultant force[blank_end] [blank_start]causing this acceleration[blank_end]. 6. [blank_start]This is known as a[blank_end] [blank_start]centripetal force[blank_end].

Select the force that is causing the centripetal force in each situation. 1. The Moon orbiting the Earth in a circle: [blank_start]GRAVITY[blank_end] 2. A car going round a bend: [blank_start]FRICTION[blank_end] 3. A spinning fairground ride: [blank_start]TENSION[blank_end] 4. A bucket swinging on a rope: [blank_start]TENSION[blank_end] 5. Standing still despite our planet spinning: [blank_start]GRAVITY[blank_end]

Give the three factors that affect centripetal force:

To increase the centripetal force, you can: - Increase the mass of the object - Increase the speed of the object - Increase the radius of the object

Fill in the blanks to reveal three examples of pendulum usage in everyday life. Gr[blank_start]andfather[blank_end] cl[blank_start]ocks[blank_end], pl[blank_start]ayground[blank_end] sw[blank_start]ings[blank_end], fa[blank_start]irground[blank_end] ri[blank_start]des[blank_end]