chapter 8 year 1 mech

Question 1

give unit for mass

Answer 1

kg (kilograms)

Question 2

give unit for length/displacement

Answer 2

m (metres)

Question 3

give unit for time

Answer 3

s (seconds)

Question 4

give unit for speed/velocity

Answer 4

m s^-1 (metres per second)

Question 5

give unit for acceleration

Answer 5

m s^-2 (metres per second squared)

Question 6

give unit for force/weight

Answer 6

Newtons or kg m s^-2

Question 7

what does gradient of displacement-time graph represent

Answer 7

velocity

Question 8

what does gradient of velocity-time graph represent

Answer 8

acceleration

Question 9

what does area under graph on velocity-time graph represent

Answer 9

distance

Question 10

using a method from yr1 pure, how can we work out gradient of velocity-time graph (acceleration)

Answer 10

use differentiation

Question 11

using a method from yr1 pure, how can we work out area under curve of velocity-time graph (distance)

Answer 11

use integration

Question 12

what do the letters of suvat represent

Answer 12

s = displacement
u = initial velocity
v = final velocity
a = acceleration
t = time

Question 13

what does it mean if somethings a paritcle

Answer 13

• dimensions of object are negligible meaning mass of object concentrated at single point.
• rotational forces/air resistance can be ignored

Question 14

give an example of a particle and why is it actually modelled in this way

Answer 14

• mass
• dimensions are negligible and rotational forces as well as effects of air resistance can be ignored

Question 15

what does it mean if something is on a rough/smooth surface

Answer 15

• objects in contact with surface does/doesnt experience friction

Question 16

what does it mean if you model a smooth/light pulley

Answer 16

• no friction so tension same in string either side of pulley
• pulley has no mass

Question 17

what does it mean if string is inextensible

Answer 17

• string doesnt stretch under load meaning acceleration the same in any connected objects/ objects connected by a taut

Question 18

what does it mean if string has light mass

Answer 18

• mass is negligible

Question 19

what does something being a rod mean

Answer 19

• its one dimension if negligible (like pole or beam) meaning mass is concentrated along line –> rigid (wont bend, stretch or compress)
• has no thickness

Question 20

what is a peg/support

Answer 20

• support from which a body can be suspended or rested meaning dimensionless and fixed.
• can be rough or smooth depending on question

Question 21

what is lamina

Answer 21

• object with area but negligible thickness (sheet of paper)
• mass is distributed across a flat surface

Question 22

what is a uniform body

Answer 22

-mass is distributed evenly (concentrated at single point at geometrical centre of object i.e. centre of mass)

Question 23

what is a light object

Answer 23

• mass of object is small compared to other masses
• like string or pulley

Question 24

what do we treat a light object as having

Answer 24

• zero mass
• tension same at both ends of a light string

Question 25

what is a wire

Answer 25

• rigid, thin length of metal that is treated as 1-dimesnional

Question 26

what is a bead

Answer 26

• particle with hole in it for threading on a wire or string so it can move freely
• tension is the same on either side of bead

Question 27

what is air resistance

Answer 27

• resistance experienced as object moves through air

Question 28

how is air resistance usually modelled

Answer 28

• being negligible

Question 29

what is gravity

Answer 29

• force of attraction between all objects
• assume all objects with mass are attracted towards earth

Question 30

how is acceleration due to gravity denoted

Answer 30

g

Question 31

what is earths gravity

Answer 31

• uniform and acts vertically downwards
• 9.8 m s^-2