all experiments

Question 1

method to determine g - trap door and

Answer 1

• set up an electromagnet over a trap door
• when current switched off ball drops and timer starts
• when ball hits trap door and timer stops
  s = 1/2 gt^2
• low current that just holds ball to reduce delay in turing off
• if distance too big air resistance will have an effect
• measure from bottom of ball

Question 2

method to determine g - light gate

Answer 2

• use a light gate - connected to data logger and computer
• drop a card through the light gate
• measure length of card (L) and height above gate (s)
  v = L/t
  v^2 = 2as
• assumed velocity is constant through gate - measure from middle fo the card
• use a ball/ bluetack to make card more stable

Question 3

measuring terminal velocity of a ball

Answer 3

• set up a tube with elastic bands at = distances
• user camera with timer in frame
• start recording and drop ball
• use magnet to get ball out
• v = d/t
• plot a graph of v against t and where it plateus is terminal v
• repeat to find average v for each time period
• use longer cylinder to increase distance

Question 4

find CoM of an object

Answer 4

• make 3 holes in random places
• hang shape from hole
• use plumb line to draw line
• repeat for all holes
• where lines cross is CoM
• make sure shape has come to rest before drawing line

Question 5

finding YM of a wire

Answer 5

• measure diameter of wire with micrometer - 3 places and average
• measure length of wire
• add weights - measure mass and extension
• use vernier scale as small x
• x = FL/A*YM
• plot x against m (F=mg)
• dont load past breaking point
• dont stand below hanger incase it drops

Question 6

investigating spring/ string stretching

Answer 6

• attach marker to a wire
• have ruler in fixed position
• add masses to hanger - measure using balance
• measure extension
• mg = kx
• at start masses must be enough to keep wire taught
• dont load past breaking point
• dont stand below hanger incase it drops

Question 7

brownian motion experiment

Answer 7

• use a slide containing particles of smoke and air
• focus microscope
• shows particles are continuously moving randomly in different directions at different speeds - due to collisions with other particles

Question 8

specific heat capacity

Answer 8

• weight block/ liquid (m)
• connect heater to circuit with ammeter and voltmeter
• allow the heater to heat up
• start a timer and place in block with thermometer
• record t and temp at different intervals
• IVt = mcT
• insulate block
• whole heater in block
• ## IV fluctuate so take measurements and average

Question 9

specific latent heat fusion

Answer 9

• weight mass of ice in funnels
• insert heater into left funnel
• connect to ammeter and voltmeter
• place on a zeroed balance
• start timer
• turn on heater
• find difference in masses
  IVt = (mL-mR)Lf
• insulate funnel
• whole heater in funnel
• IV fluctuate so take measurements and average

Question 10

specific latent heat vaporisation

Answer 10

• measure mass of water in the kettle
• start a timer
• heat the kettle - connect to a power meter and zero it when steam starts forming
• once 5 mins is over stop heating and measure new mass
• Pt = mL
• heat whole kettle

Question 11

investigating circular motion

Answer 11

• attach bung to a string
• measure mass of the bung using an electronic balance
• measure lenght of string
• hang masses from the other end
  F = Mg
• record spins with a video camera and timer in frame - find time for 40 oscillations and /40
• v = 2pir/T
  Mg = mv^2/r
• keep string horizontal
• keep radius constant
• make sure bung isnt too heavy to hit anyone

Question 12

investigating SHM

Answer 12

• set up pendulum
• mark equilibrium
• record oscillations with a video camera and timer in frame - find time for 40 oscillations and /40
• f = 1/T
• measure oscillations from equilibrium
• air resistance reduces amplitude

Question 13

PV - boyles law

Question 14

PT

Question 15

VT