Year 1 - Mechanics

Question 1

8.2 What are the modelling assumptions for a particle?

Answer 1

Mass concentrated at a single point, Rotational forces/air resistance ignored

Question 2

8.2 What are the modelling assumptions for a rod?

Answer 2

One dimension is negligible, mass concentrated along a line, rigid

Question 3

8.2 What are the modelling assumptions for a lamina?

Answer 3

Thickness is negligible, mass is distributed across a flat surface

Question 4

8.2 What are the modelling assumptions for a uniform body?

Answer 4

Mass concentrated at the object’s centre of mass

Question 5

8.2 What are the modelling assumptions for a light object?

Answer 5

The object has zero mass

Question 6

8.2 What are the modelling assumptions for an inextensible string?

Answer 6

String does not stretch under load, acceleration is the same in any connected objects

Question 7

8.2 What are the modelling assumptions for a smooth surface?

Answer 7

The surface experiences no friction

Question 8

8.2 What are the modelling assumptions for a rough surface?

Answer 8

The surface experiences friction between it and any object in contact with it

Question 9

8.2 What are the modelling assumptions for a wire?

Answer 9

Rigid, thin line of metal, one dimensional

Question 10

8.2 What are the modelling assumptions for a smooth and light pulley?

Answer 10

No friction, no mass, tension is the same in string on either side of the pulley

Question 11

8.2 What are the modelling assumptions for a bead?

Answer 11

Particle with a hole that moves freely along a wire/string

Question 12

8.2 What are the modelling assumptions for a peg?

Answer 12

A single point with no dimensions from which an object is suspended on, can be rough or smooth

Question 13

8.2 What are the modelling assumptions for air resistance?

Answer 13

Usually modelled as negligible

Question 14

8.2 What are the modelling assumptions for gravity?

Answer 14

Gravity is uniform and acts vertically downwards

Question 15

9.4 Name the 5 suvat equations

Answer 15

v = u + at

s=((u + v)/2)t

v^2 = u^2 + 2as

s = ut + (1/2)at^2

s = vt - (1/2)at^2

Question 16

10.1 What is Newton’s First Law?

Answer 16

An object in motion remains in motion unless acted upon by a resultant force

Question 17

10.2 How do you find the resultant of two or more forces as a vector?

Answer 17

By adding the vectors

Question 18

10.3 What is Newton’s 2nd Law?

Answer 18

F = ma

Question 19

10.3 What is the equation that links weight, mass, and gravitational field strength?

Answer 19

W = mg

Question 20

10.5 What can you say if all the particles in a system are moving in the same straight line?

Answer 20

They can be considered as one particle

Question 21

10.5 What is Newton’s 3rd Law?

Answer 21

Every action has an equal and opposite reaction

Question 22

10.6 What is a smooth pulley?

Answer 22

The tension in the string is the same on both sides of the pulley

Question 23

11.1 What is represented by the gradient of a displacement-time graph?

Answer 23

Velocity

Question 24

11.1 What is represented by the gradient of a velocity-time graph?

Answer 24

Acceleration

Question 25

11.2 If displacement, s, is expressed as a function of t, what can the velocity be expressed as?

Answer 25

v = ds/dt

Question 26

11.2 If displacement, s, is expressed as a function of t, what can the acceleration be expressed as?

Answer 26

a = d^2s/dt^2

Question 27

11.3 How do you find the maximum displacement given an equation for displacement in terms of time?

Answer 27

Max. displacement is given by the turning point, to find it differentiate the equation and set ds/dt=0

Question 28

11.5 What can you use calculus to do when given an equation for displacement, velocity, or acceleration?

Answer 28

Use differentiation or integration to derive formulae for the displacement, velocity, or acceleration