Mock 2010

A 2kg object moving with a velocity of 8m/s collides with a 4kg object moving at a velocity of 5 m/s along the same line.

If the 2 objects join on impact calculate their common velocity when they

1. in opposite directions
2. travelling in the same direction

(12)

Describe the apparatus that might have been used to carry out this experiment

(9)

What might have held the two objects together

(6)

What readings needed to be taken in order to calculate the velocity

(6)

Why does this experiment need to be carried out in a closed system

(7)

Q2

A student passed a ray of light through a rectangular glass block from air. He measured the angles of incidence for five rays of light entering the glass block and the cooresponding angles of refraction the following results were obtained

Answer all the following parts

1. When would an object moving at constant speed have an acceleration
2. If the Potential energy of a body is 980J at a height of 2m, what is the weight of the body
3. The critical angle for water is 48.6^o . Find its refractive index.
4. A diffraction grating has 500 lines per mm. What is the distance in meters between adjacent lines.
5. Give a use of capacitors
6. State Lenz' law
7. Who discovered radioactivity in 1890
8. What initiates the fission of a Uranium nucleus
9. Name 2 factors on which the back emf of a motor depend
10. Distinguish between baryons and leptons.

Q6

Distinguish between a scalar quantity and a vector quantity

(6)

Describe an experiment to find the resultant of two vectors.

(18)

Define acceleration

(6)

A body is travelling with a velocity u in a certain direction. It then uniformly accelerates, a, in the same direction for a time t. Derive a expression for its displacement after time t in terms of u and a

(11)

A car accelerates from rest to a speed of 15m/s in a time of 4 seconds. it then moves at this speed for the next 6 s

Calculate

1. The total distance travelled by the car.
2. The average speed of the car

(15)

Q7

Explain the term Resonance. Give an example

(9)

A tuning fork is set vibrating over a resonance tube which can be varied from 0cm to 110cm in lenght. At what lenghts would you expect to find resonance if the tuning fork has a frequency of 425Hz and the speed of sound in air is 340m/s

(12)

In the Laboratory, the vibrating tuning fork is held slightly above the resonance tube. How is this error in the measurement overcome?

(6)

A police car siren emits a continous note of frequency 1kHz as it passes a stationary observer at traffic lights if the police car is travelling at 30m/s towards the observer the frequency of the note appears higher. Explain using a diagram why the note appears to be higher. Name this phenomena.

(14)

If the velocity of sound is 336 m/s on this particular day what is the frequency heard by the observer when the car is

1. approaching the observer
2. moving away from the observer

Give another application of this phenonmen.

(15)

Q8

Explain the term radioactive decay

(6)

Radon-222 is an alpha emitter. Write an equation to show the decay of radon-222.

(6)

Why is radon considered to be a health hazard

(5)

In an experiment to determine the half-life of a short lived radioactive isotope a measure of the activity A for a sample of the isotope was obtained at various times t, the following results were recorded

Q11

If the velocity of sound is 336 m/s on this particular day what is the frequency heard by the observer when the car is

Q12

If the velocity of sound is 336 m/s on this particular day what is the frequency heard by the observer when the car is