Physics Paper 1 Marking Scheme
KCSE CLUSTER TESTS 27
Physics Paper 1
SECTION A (25 Marks)
Answer all the questions in the spaces provided.2 marks
1 marks
The 10kg√ one, hot air containing CO2 rises from the short to the long candle extinguishing it. √
2 marks
Becomes less stable. √When the water freezes it expands raising the position of centre of gravity.
3 marks
3 marks
They move towards each other/closer. √ The blown air increases the speed of the air between them. This reduces pressure√ between and external pressure/atmospheric pressure pushes them together.
2 marks
Surface tension pulls the film inside as it tries to get the smallest surface area. √
3 marks
– Force pump can raise liquid to any height unlike lift pumps which are restricted by atmospheric pressure. √
- Force pump delivers liquid in both up and down strokes while lift up pump delivers liquid on up stroke
- Force pump delivers liquid continuously while lift pump delivers it at intervals√.
2 marks
The air particles are in the constant random motion, they collide with the walls √and their change in momentum per unit time/rate of collision causes pressure.
2 marks
The heat energy is used to break the bonds/intermolecular forces√ holding the liquid particles together
1 marks
A, √it has less number of turns hence less stiffer. √
2 marks
Sum of clockwise moments = Sum of anticlockwise moments
2 marks
It increases/lengthens the time√ of impact hence reducing velocity impulse.
1 marks
The body is moving with an increasing non-uniform acceleration. √
2 marks
SECTION B (55 Marks)
Answer all the questions in this section in the spaces provided.a) Heat, sound, light, chemical, potential ,kinetic e.t.c√
b) i) work done = force x distance√
= 20,000 x 3.0 = 60,000 J √
11 marks
a) The velocity reduces/decreases with time.
c) i) Gravitational force of the earth. √
ii) Towards the centre of the earth. √
iii) I. –√
= – x 3
= 18.85rad/s√
ii. Tension = mw2r – mg√
8 marks
a) i) 220C√
ii) - Some heat lost due to poor thermal contact√
- Some is used to heat/heating up of the oil of the immersion heater. √
iii) The heating element remained hot Lime continuity to heat the block. √
iv) Heat lost = heat gained
MC∆Ѳ = Vlt
2kg x C x (52-30) = 22 x 10 x (5-2) x 60
b) – Some heat energy is lost due to poor lagging
- Poor contact and in raising the internal energy the particles in the solid.
8 marks
a) Provided there is no external force acting on a system of colliding bodies the sum of momentum of the system remains constant.
b)
i) co-efficient of friction µ = 7f/mg√
c) Backward forces were greater than the forward forces since water surface posses less
10 marks
b) – Density has units relative density has no units
- Relative density compares or is the number of times a substance is denser than water while density mass per unit of volume of a substance.
10 marks