## Physics 2010 | Study Mode

Question 1
A
30 kmh-1
B
130 kmh-1
C
200 kmh
D
230 kmh-1
Explanation.
Since the cars are moving in the same direction, the velocity of a body A, Va,relative to another body B, Vb is given by V = Va - Vb
the velocity of faster car is measured by the observer in the slower car is V = 130kmh-1 - 100 kmh-1 = 30 kmh-1

Question 2
A
the feather will be brown away by the wind while stone will drop steadily
B
the stone and the feather will both reach the ground a the same time
C
the feather will reach the ground first
D
the stone will reach the ground first
Explanation.
The acceleration of free fall due to gravity is independent of mass of the body. Therefore, ignoring air resistance, which affects feather more than the stone, the stone and the feather will both reach the ground at the same time

Question 3
A
2 ms-2
B
5 ms-2
C
20 ms-2
D
25 ms-2
Explanation.
Acceleration = (increase in velocity)/time taken
= (45 - 25)/10 = (20)/10 = 2ms-2

Question 4
A
B
C
enable them to carry more load
D
make them stronger
Explanation.
Rough surface promotes friction. Therefore, roughness of conveyor belt prevents the load from slipping

Question 5
A
55. 6 %
B
50.0%
C
33.3%
D
22.2%
Explanation.
Efficiency = (MA)/V.R x 100% = (load)/Effort x (1)/V.R
= (800)/400 x (1)/6 x 100% = 33.3%

Question 6
A
0.75 J
B
7.50 J
C
75.00 J
D
750.00 J
Explanation.
Energy stored in a stretched wire (strain energy)
= average force x extension
= (1)/2 Fe
= (1)/2 x 300 N (30.5 - 30.0) x 10-2 m
= (300)/2 x 0.5 x 10-2 = 0.75J

Question 7
A
300 N
B
200 N
C
150 N
D
100 N
Explanation.
Thrust = pressure x area = 100 pa x 3 m2 = 300 N

Question 8
A
a density bottle
B
an eureka can
C
a pipette
D
a burette
Explanation.
Since relative density = mass of substance
mass of equal volume of water relative density bottle should be used to determine the mass of the substance, and mass of an equal volume of water by filling the bottle with the powder and water respectively and weighed with the beam balance.

Question 9
A
vapour pressure of a fluid
B
density of liquid
C
relative humidity of a liquid
D
relative density of a liquid
Explanation.
The instrument used in measuring relative density is hydrometer

Question 10
A
low density
B
low freezing point
C
high specific
D
low boiling point
Explanation.
The low freezing point of alcohol, -115c enable low temperatures to be measured. mercury freezes at 39c, and cannot be used in countries like Russia where winter temperatures of -40c are common

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