AS Mechanics

Question 1

What is a particle?

Answer 1

a body whose dimensions, except for mass are negligible

Question 2

Where is the mass concentrated in a particle

Answer 2

concentrated at a single point

Question 3

Which forces can be ignored when regarding a particle?

Answer 3

Rotational forces
Air resistance

Question 4

What is a bead?

Answer 4

A particle with a hole in it for threading on a wire or a string

Question 5

Where is tension on a bead?

Answer 5

Tension is the same either side

Question 6

What is a wire?

Answer 6

Rigid thin strip of metal

Question 7

What modelling assumption is made about wires?

Answer 7

Treated as one dimensional

Question 8

What is a rod?

Answer 8

An object whose mass is concentrated along a line
All dimensions but one are negligible

Question 9

What is meant by the term negligible?

Answer 9

small enough that it can be ignored

Question 10

What is a uniform rod?

Answer 10

One which equal lengths have equal masses - means that the weight can be taken from the centre

Question 11

What is a light object?

Answer 11

One whose mass in negligible

Question 12

What is a lamina?

Answer 12

A flat body having area but negligible thickness

Question 13

What is a uniform lamina?

Answer 13

One which equal areas of lamina have equal masses

Question 14

What is a peg?

Answer 14

A pin from which a body can be suspended or rested

Question 15

Is a peg dimensionless?

Answer 15

yes

Question 16

Difference between a smooth and rough peg

Answer 16

Smooth peg has no friction
Rough peg would have a frictional force

Question 17

What is an inextensible/inelastic string and what does this mean for particles attached?

Answer 17

one that doesnt stretch and length never changes
Acceleration is the same for all particles attached to a taut string

Question 18

What is meant by a smooth surface?

Answer 18

One which offers no resistance to motion eg no friction

Question 19

What is meant by a rough surface?

Answer 19

One where friction has to be taken into account

Question 20

What is a smooth pulley and what does this mean for tension?

Answer 20

One with no friction in its bearings - tension in the string will be equal on the two sides of the pulley

Question 21

What is a plane surface?

Answer 21

A completely flat surface

Question 22

What is weight?

Answer 22

force acting on an object due to gravity

Question 23

What is resistance?

Answer 23

any force that opposes the motion of an object

Question 24

What is friction?

Answer 24

type of resistance force caused when objects are trying to slide against one another

Question 25

What is reaction force ?

Answer 25

when two objects are in contact, each exert a reaction force on the other

Question 26

What is the direction of a reaction force?

Answer 26

perpendicular to the surface on contact

Question 27

What is a driving force?

Answer 27

force applied to an abject to cause it to move

Question 28

What is braking force?

Answer 28

force applied to a moving object with the intention of slowing it down

Question 29

What is tension?

Answer 29

force produced by an object that prevents it being stretched

Question 30

What is thrust / compression?

Answer 30

force produced by an object that prevents it being squashed

Question 31

What is lift?

Answer 31

an upwards force that acts on an aircraft enabling it to take off

Question 32

What is buoyancy?

Answer 32

an upwards force acting on an object floating on water that stops it from sinking