Moments Levers and Gears

Question 1

Moment

Answer 1

-turning effect of a force around a fixed point (pivot)

Question 2

Moment examples

Answer 2

-door opening around a fixed hinge
-seesaws
-scissors
-spanner turning round a nut

Question 3

What are moments measured in?

Answer 3

Newton metres (Nm)

Question 4

Moments equation

Answer 4

moment = force x times perpendicular distance to the pivot

Question 5

The bigger the perpendicular distance/force….

Answer 5

….the bigger the moment.

Question 6

True or False: Objects can experience more than one moment

Answer 6

True

Question 7

When the total clockwise
moment about a
pivot is equal to the total anticlockwise moment about that pivot….

Answer 7

…the object is balanced.

Question 8

Lever

Answer 8

-simple machine consisting of a pivot, effort and load

Question 9

The longer the lever/the further the effort acts from the pivot…

Answer 9

….the greater the force on the load will be.

Question 10

What do levers use to act as a force multiplier?

Answer 10

Moments

Question 11

What is the primary function of levers?

Answer 11

To allow a larger force (moments) to act upon the load than is supplied by the effort

Question 12

True or False: Levers make it harder to move large or heavy objects.

Answer 12

False

Question 13

Fill in the blank: Levers act as a _______ by allowing a larger force to act upon the load.

Answer 13

force multiplier

Question 14

A solid beam 0.5 m long is laid across a pivot to form a simple lever. The pivot is 0.1 m from the end of the beam. Calculate the heaviest load that could be lifted using a force of 500 N.

Answer 14

-calculate the greatest distance from the pivot:
0.5-0.1 = 0.4
-use the values to calculate the moment:
500 x 0.4 =200 Nm
-then rearrange M = F x d to find F
? x 0.1 =200Nm
200/0.1 = 2000Nm

Question 15

Gears

Answer 15

-force multipliers
-rotate wheels with teeth that interlock with another wheel

Question 16

How are gears force multipliers?

Answer 16

-used to multiply rotational forces

Question 17

Axle

Answer 17

-rod that passes through a gear, which the gear rotates around

Question 18

Ratio of moments in gears

Answer 18

number of teeth of gear 1: number of teeth of gear 2

Question 19

Both adjacent gears move upwards or downwards…

Answer 19

….so they must move in opposite directions.

Question 20

How do gears work?

Answer 20

-turning force applied to one wheel
-interlocking wheel turns adjacent wheel in opposite direction
-cogs prevent wheels from slipping

Question 21

Driving Gear

Answer 21

-the gear where the input force or power comes from

for example, the pedals on a bike turn the driving gear

Question 22

Driven gear

Answer 22

-the gear that the driving gear is directly in contact with and causes to rotate

Question 23

If the driven gear is made larger is will rotate more…

Answer 23

…slowly but with a greater moment.

Question 24

If the driven gear is made smaller it will rotate more…

Answer 24

…quickly but with a smaller moment.