(b) The student did 2240 J of work going from the bottom of the stairs to the top of the stairs.
The student took 2.8 seconds to run up the stairs.
(i)
Calculate the power the student developed when running up the stairs.
(2)
(ii)
How much gravitational potential energy did the student gain in going from the
bottom to the top of the stairs?
Tick (V) one box.
much more than 2240 J
2240 J
much less than 2240 J
(1)
(Total 4 marks)
Answers
(b) (i) 0.6.109
(ii) mass halved
speed halved
(speed)2 quartered
ke and/or power cut to one eight
for 1 mark each
5
[8]
M5.(a) g.p.e. = mass × gravitational field strength × height
accept Ep = mgh
1
(b) Ep = 50 × 9.8 × 20
1
9800 (J)
allow 9800 (J) with no working shown for 2 marks
answer may also be correctly calculated using W = Fs
ie allow W = 490 × 20 for 1 mark
or answer of 9800 (J) using this method for 2 marks
1
(c) 7840 (J)
allow ecf from ‘11.2’
1
(d) 7840 = ½ × 50 × v2
v=√7840
______
1/2 ×50allow for this point
1
17.7(0875) (m / s)
1
18 (m / s)
allow ecf from ‘11.3’ correctly calculated for 3 marks
allow 18 (m / s) with no working for 2 marks
answer may also be correctly calculated using v2 – u2 = 2as
1
(e) extension = 35 (m) and conversion of 24.5 kJ to 24500 J
1
24 500 = ½ × k × 352
1
40
1
allow 40 with no working shown for 3 marks
an answer of ‘16.2’ gains 2 marks
this is the answers I know but I am sorry any mistakes are there
Answer:
f
Explanation: