Revision Tracker for Y9

This is for the whole year.. You won't be examined on topics we have yet to do.

http://twyfordigcsephysics.blogspot.co.uk/p/revision.html

Stretching a Wire

http://twyfordigcsephysics.blogspot.co.uk/2013/05/stretching-wire.html

Mark Scheme assessed homework

1.       (a)     friction                                             if more than one box is ticked, award   1 (L3)
                                                         no mark

(b)     (i)      it gets longer                            accept ‘it is more’                                 1 (L3)

(ii)     any one from                                                                                       1 (L4)

·   there is less friction or grip

·   the road is slippery             accept ‘water is a lubricant’

(iii)    it gets longer                            accept ‘it is more’                                 1 (L3)

(iv)    concrete                                                                                               1 (L4)

[5]

  2.     (a)     one mark is for the correct value and the other mark is for the corresponding unit

either

·   1500                                            accept ‘100 × 15’                                 1 (L7)

·   N cm or newton cm                                                                                  1 (L7)

or

·   15                                                accept ‘100 × 0.15’

·   N m or newton metre

  (b)   exert a larger force                           answers may be in either order             1 (L7)

accept ‘use a bigger force’ or ‘push harder’
do not accept ‘exert a larger pressure’

          exert the force further away from the nut                                                      1 (L7)

accept ‘push down further from the nut’ or ‘exert the force further along the spanner’
do not accept ‘use of a longer spanner’

[4]

  3.     (a)     down                                                                                                             1 (L3)

(b)     B and D                                            letters may be in either order both        1 (L3)
                                                         letters are required for the mark

accept 112 and 112

  (c)   down                                                                                                             1 (L3)

(d)     E                                                                                                                    1 (L3)

(e)     any two from                                                                                                2 (L4)

·   put the gold coin in one pan and a silver coin or coins in the other

·   add or replace or remove silver coins

·   see which pan goes up or see which way the scales move

accept ‘see if it balances’

·   it is heavier than the silver coins which go up

·   it is lighter than the silver coins which go down

accept ‘try each silver coin to see which one balances the gold coin’ for two marks

[6]

  4.     (a)     (i)      75                                           accept ‘50 × 1.5’                                  1 (L7)
Nm                                                                                                       1 (L7)

do not accept lower case n

(ii)     750                                         accept ‘‘ or ‘50 × 15’              1 (L7)
                                               accept the numerical answer to part (i) ÷ 0.1

  (b)   any one from                                                                                                 1 (L7)
·  a current flows in the coil
·  the coil or the iron core                accept ‘there is a magnetic field’ or ‘the
   becomes magnetised                     electromagnet switches on

do not accept ‘the core becomes magnetic’

          any one from                                                                                                 1 (L7)
·  the counterweight is attracted
   to the coil or core or the
   electromagnet
·  the electromagnet produces a       accept ‘the left-hand side of the barrier
   bigger moment                              moves down’

‘the right-hand side moves up’ is insufficient

[5]

5.       (i)      (when a system is in equilibrium) the sum of the anticlockwise
moments equals the sum of the clockwise moments (about the same pivot)         B1

(ii)     sum of the forces equals zero / resultant force is zero                                          B1
sum of the moments equals zero      B1

[3]

6.       (sum of) clockwise moment(s) = (sum of )
anticlockwise moment(s)

Not: ‘CWM = ACWM’

C1

          (18 × 0.14) + (60 + 0.32) = 0.035F

Allow: working in consistently in cm

C1

          F ≈ 620 (N)

Note: Bald answer scores 3 marks
Allow: 1 mark for 21.72 (N m) or 2172 (N cm)

A1

[3]

 7.      (a) Any three from:
1. (Suspend plate from a point and then) mark a
    vertical line on the plate (wtte)
2. Plumb line / ‘pendulum’ (used to find the vertical
    line)
3. Hang from another point / place (and draw
    another vertical line) (wtte)
4. Where the lines intersect gives position of centre
    of gravity (wtte)

Note: For 1st point accept ‘mark line of string’

Allow: 1 mark for ‘By trial and error find a position where the plate balances’

B1 × 3

          (b) (i) moment = 6.0 × 0.40
moment = 2.4 (N m)

B1

(ii)     Weight / force acts through the pivot
Or (perpendicular) distance from pivot is (reduced to)
zero (wtte)

Allow: weight is ‘vertically below’/‘directly below’ the pivot
Reference to pivot / point P (wtte) is essential

B1

[5]

Elasticity

http://twyfordigcsephysics.blogspot.co.uk/2013/05/elasticity.html