Physics – Half Yearly Examinations 2015 – Form 4 – Track 2 Page 1 of 11

FORM 4 PHYSICS TIME: 1h 30min

Name: ________________________________________ Class: _____________

Answer ALL questions in the spaces provided on the exam paper.

All working must be shown. The use of a calculator is allowed.

Where necessary take the acceleration due to gravity, g to be 10 m/s2.

Forces & Motion

W = m g F = m a

v = u + a t s = u t + ½ a t2

s = 2

v) (u t v2 = u2 + 2 a s

time Total

distance Total speed Average Momentum (p) = m v

Waves v = f λ T

1 f

Number 1 2 3 4 5 6 7 8 Total

Maximum mark 8 8 8 8 8 15 15 15 85

Actual mark

Total Theory Total Practical Final Mark

Actual Mark

Maximum Mark 85 15 100

February 2015 Track 2

Kulleġġ San Nikola Sekondarja tas-Subien, In-Naxxar St. Nicholas College Naxxar Boys Secondary

Half-Yearly Examinations February 2015

Physics – Half Yearly Examinations 2015 – Form 4 – Track 2 Page 2 of 11

SECTION A This section carries 40 marks

1. The distance-time graph shown below shows the motion of a man during a short

ride with his bike:

a. Describe the motion of the boy

i. Between 0 to 30 s (1)

_________________________________________________________________________________

ii. Between 30 to 50 s (1)

_________________________________________________________________________________

b. i. What is the distance travelled after 15 s? _________________________________ (1)

ii. At what time is the distance travelled 100 m? ______________________________ (1)

c. From the graph, or otherwise, calculate the speed at which the boy cycles,

between 50 to 80 s. (2)

_________________________________________________________________________________

_________________________________________________________________________________

d. On the graph, mark with letters AB the part of the graph where the boy is travelling

fastest. Explain why you chose this part. (2)

_________________________________________________________________________________

_________________________________________________________________________________

distance-time graph d

ista

nce

(m

)

(m)(

m)

time (s)

Physics – Half Yearly Examinations 2015 – Form 4 – Track 2 Page 3 of 11

2. In a drag race a car starts from rest on a straight track and accelerates uniformly to

reach a velocity of 120 m/s in 5 s.

a. What is the initial velocity, u, of the car? __________ (1)

b. What is the final velocity, v, of the car? __________ (1)

c. Calculate the acceleration of the car. (2)

_________________________________________________________________________________

_________________________________________________________________________________

d. Find the distance moved during these 5 s. (2)

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

e. If the total mass of the car and driver is 1400 kg, what is the resultant force on them?

_________________________________________________________________________________

_________________________________________________________________________________

f. Use your answer from part e) to calculate the driving force produced by the engine

if the total force opposing the motion of the car is 4000 N. (1)

_________________________________________________________________________________

_________________________________________________________________________________

3. Steve is driving at 45 m/s. The car in front of him stopped suddenly and he had to

react quickly and press the brake pedal.

a. Define the following term and mention one factor that affects it. (2)

Definition Factor

Braking

distance

b. Steve takes 0.8 s to reach and press the brake pedal. What is the distance travelled

during this time? (2)

_________________________________________________________________________________

_________________________________________________________________________________

(1)

Physics – Half Yearly Examinations 2015 – Form 4 – Track 2 Page 4 of 11

c. After pressing the brake pedal it took him a distance of 50 m to bring the car to a

stop. Calculate:

i. The total stopping distance. (1)

_________________________________________________________________________________

ii. The total time taken to stop the car. (2)

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

d. Had Steve been using a mobile phone, how would this affect the thinking

distance? (1)

_________________________________________________________________________________

_________________________________________________________________________________

4. Jack jumps off from a helicopter wearing a parachute. He does not open the

parachute straight away. The graph below shows the velocity (y-axis) against time

(x-axis) during the first 10 seconds after Jack jumps.

a. What is his velocity 2 seconds after he jumped? (1)

_________________________________________________________________________________

b. After how many seconds does he open his parachute? (2)

_________________________________________________________________________________

c. As the boy falls, forces are acting upon him.

i. What is the force that is pulling him down called? (1)

_________________________________________________________________________________

Physics – Half Yearly Examinations 2015 – Form 4 – Track 2 Page 5 of 11

ii. What is the force acting upwards, opposing his motion, called? (1)

_________________________________________________________________________________

d. Which of the forces mentioned in (c) above is larger:

i. At 3 seconds? _______________________________________________________ (1)

ii. At 6 seconds? _______________________________________________________ (1)

e. Describe briefly the motion of skydiver after 8 seconds that he falls. (1)

_________________________________________________________________________________

5. Two fishermen in different boats are 40 m apart when a speedboat passes creating a

wave which causes the fishermen to bob up and down as shown in the diagram below.

a. Is the wave causing the fishermen to bob up and down a transverse or a

longitudinal wave? __________________________________________________________ (1) (1)

b. On the diagram above mark:

i. a crest with a letter C

ii. a trough with a letter T

iii. a wavelength with the symbol λ. (3) (3)

c. Calculate the wavelength of the water wave shown in the diagram. (1)

_________________________________________________________________________________

d. If the fishermen bob up and down once every 4 seconds until the speedboat wave

passes. What is the periodic time T of the wave? (1)

_________________________________________________________________________________

e. What is the frequency of the speedboat wave? (1)

_________________________________________________________________________________

f. Using your answers calculate the velocity of the wave. (1)

_________________________________________________________________________________

_________________________________________________________________________________

40m

Wave direction

Physics – Half Yearly Examinations 2015 – Form 4 – Track 2 Page 6 of 11

SECTION B This section carries 45 marks

6. The following table shows the velocity of a car as it is moving along a level road.

velocity (m/s) 0 7.5 15 22.5 30 30 30 20 10 0

time (s) 0 5 10 15 20 30 40 50 60 70

a. Plot a graph of velocity in m/s on the y-axis against time in seconds on the x-axis on

the graph paper provided. (5) (5)

b. Label the graph with letters:

i. AB – to show where the car was accelerating. (1) (1)

ii. CD – to show where the car was decelerating. (1) (1)

c. Work out the total distance travelled by the car during the 70 s of its journey. (4)

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

d. i. Use your graph to find the acceleration of the car during the first

20.seconds. (2)

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

ii. The mass of the car is 920 kg. Using F = ma, work out the force in N required

during the acceleration. (2)

_________________________________________________________________________________

_________________________________________________________________________________

Physics – Half Yearly Examinations 2015 – Form 4 – Track 2 Page 7 of 11

Physics – Half Yearly Examinations 2015 – Form 4 – Track 2 Page 8 of 11

7. During a physics lesson, the students were asked to investigate the behaviour of

water waves. The teacher provided the following apparatus so that they could

carry out their investigation.

a. Using the list provided, label the different components shown in the diagram of the

experimental set-up used by the students.

Light source, Shallow tank of water, Power supply, Viewing screen, Oscillating paddle, motor.

(3)

b. Describe by filling the blanks how the students used the above set up to produce

straight water waves of different frequencies and then measured the corresponding

wavelengths.

The motor’s ________________ was set from the device itself and once the motor was

set in motion the oscillating paddle moved _________ and _________ on the surface

of the ______________. This movement created _______________ wave fronts with the

same frequency as the ______________ frequency. The wavelength was found by

measuring the distance between successive __________________ on the viewing

screen by using a ______________. (4)

The students started off the experiment by investigating reflection and refraction of

water waves.

c. Complete each diagram to show how waves travel in each situation. (4)

Reflecting surface Glass block

i. ii.

Physics – Half Yearly Examinations 2015 – Form 4 – Track 2 Page 9 of 11

Finally, the students sent straight water waves towards a gap in a straight barrier as

shown in the diagram below:

d. Complete the diagram to show what happens to the waves that have passed

through the gap. (1)

e. What is this effect called? (1)

_________________________________________________________________________________

The students move the barrier to widen the gap as shown below.

f. Sketch on the diagram above how the waves on the other side of the gap would

look now. (1)

This same effect is experienced by radio waves as they travel over hills.

g. Which are diffracted more - long wavelength radio waves, or shorter wavelength TV

waves? (1)

_________________________________________________________________________________

Physics – Half Yearly Examinations 2015 – Form 4 – Track 2 Page 10 of 11

8. This question is about momentum.

a. A student wanted to investigate the principle of conservation of momentum using 2

wooden trolleys and a smooth, inclined runway which was compensated for

friction. He also used two light gates and two electronic timers to calculate the

velocities of the trolleys.

He measures the mass of each trolley using an electronic balance and then pushes

trolley A towards trolley B. Trolley B is initially at rest. He obtains the following results:

mass of trolley A = 0.350 kg,

mass of trolley B = 0.275 kg

velocity of trolley A (before collision) = 2.6 m/s

i. Calculate the momentum of trolley A, before it collides with trolley B. (2)

_________________________________________________________________________________

_________________________________________________________________________________

ii. What is the momentum of trolley B when it is at rest before the collision? (1)

_________________________________________________________________________________

iii. Hence calculate the total momentum of both trolleys before collision. (1)

_________________________________________________________________________________

iv. After the collision, the two trolleys stick together. What is their total momentum

after collision? (1)

_________________________________________________________________________________

v. By applying the principle of conservation of momentum, calculate the

combined velocity of the trolleys after collision. (3)

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

trolley A trolley B

light gate

friction-

compensated

runway

card

electronic

timer

Physics – Half Yearly Examinations 2015 – Form 4 – Track 2 Page 11 of 11

b. A baseball player catches a ball of mass 0.15 kg when it is moving with a velocity of

19 m/s and he stops it.

i. What is the momentum of the baseball before he catches it? (1)

_________________________________________________________________________________

_________________________________________________________________________________

ii. What is the final momentum of the baseball after he catches and stops it? (1)

_________________________________________________________________________________

iii. What is the change in momentum of the baseball? (1)

_________________________________________________________________________________

iv. If the force exerted by the player to stop the ball is – 285 N, use the equation

Force =time

momentum in change to calculate the time taken to stop the ball. (2)

_________________________________________________________________________________

_________________________________________________________________________________

_________________________________________________________________________________

v. If the baseball was thrown with the same velocity but is stopped in a time of

0.014.s, would the force on the player increase, decrease or remain the same?

_________________________________________________________________________________

c. Modern cars are built with a number of safety features designed to protect the

driver and passengers during a collision. Give one example of a safety feature used

in cars. (1)

_________________________________________________________________________________

(1)