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- 1. Multiple Choice
Define work done
product of force and distance moved
product of force and displacement
force x perpendicular distance from pivot
ratio of force and distance moved in direction of force
- 2. Multiple Choice
What is the unit of work?
N m-1
kg m s¯²
kg m² s¯²
kg m² s¯³
- 3. Multiple Choice
What is potential energy?
energy stored due to height above the surface of Earth
stored energy available to do work
energy a body has due to its motion
energy stored due to deformation
- 4. Multiple Choice
Distinguish between gravitational potential energy (GPE) and elastic potential energy (EPE).
I. GPE the energy stored due to height of object above the surface of Earth
II. EPE is due to deformation of object.
III. Both are stored energy available to do work
I, II, III
I and II
I and III
III only
- 5. Multiple Choice
A
B
C
D
- 6. Multiple Choice
404 μJ
404 mJ
404 J
404 kJ
- 7. Multiple Choice
I, II
II, III
II, IV
III, IV
- 8. Multiple Choice
Define power
ratio of work done to time taken
rate of doing work
product of work and time
product of force and velocity
- 9. Multiple Choice
Wq
Wr
Wp + Wq
Wp
- 10. Multiple Choice
A bungee jumper jumps from a platform and is decelerated by an elastic bungee cord, as shown.
At which part of the jump are all three types of energy non-zero?
on the platform before the jump
on the way down before the cord has started to extend
on the way down as he decelerates
at the bottom of the jump when the is stationary
- 11. Multiple Choice
The forward motion of a motor-boat is opposed by forces F which vary with the boat’s speed v in accordance with the relation F = kv², where k is a constant.
The effective power of the propellers required to maintain the speed v is P.
Which expression relates k, P and v?
- 12. Multiple Choice
What is the efficiency of the CHP station for producing useful power?
31%
38%
50%
81%
- 13. Multiple Choice
A concrete of sides 0.60 m and uniform density 2.0 x10³ kg m¯³ is lifted 5.0 m vertically by a crane.
What is the change in potential energy of the cube?
2.2 kJ
21 kJ
59 kL
450 kJ
- 14. Multiple Choice
- 15. Multiple Choice
An escalator in an underground station has 250 people standing on it and is moving with a velocity of 4.3 ms-1. The average mass of a person is 78 kg and the angle of the escalator to the horizontal is 40o.
What is the minimum power required to lift these people?
54kW
64kW
530kW
630kW
- 16. Multiple Choice
The Atlantic torpedo is a large electric fish capable of generating a voltage of 220V between its tail and its head. This drives a pulse of current of 15A lasting for a time of 2.0 ms. The fish produces 200 pulses per second.
What is the average power output of the fish?
33W
1.3kW
3.3kW
6.6kW
- 17. Multiple Choice
A twig from a tree drops from a 200m high cliff on to a beach below. During its fall, 40% of the twig’s energy is converted into thermal energy.
What is the speed with which the twig hits the beach?
35 ms-1
40 ms-1
49 ms-1
63 ms-1
- 18. Multiple Choice
A stone of mass 0.250 kg is thrown upwards. Its velocity decrease from 20 m/s to 10 m/s. The change in kinetic energy of the stone is
1.25 J
3.75 J
37.5 J
75 J
- 19. Multiple Choice
120kJ
240kJ
360kJ
600kJ
- 20. Multiple Choice
In ‘normal driving conditions’, an electric car has a range of 150 km. This uses all of the 200MJ energy stored in its batteries.
With the batteries initially fully charged, the car is driven 100km in ‘normal driving conditions’. the batteries are then recharged from a household electrical supply delivering a constant current of 13.0A at a potential difference (p.d.) of 230V.
What is the minimum time required to recharge the batteries?
0.95 hours
12.4 hours
18.6 hours
27.9 hours
- 21. Multiple Choice
A
B
C
D
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