INTERNATIONAL TURKISH HOPE SCHOOL
UTTARA BOYS SECTION
1.
The diagram shows the side view of a
laptop computer.
A student opens the computer with an upward force of 4.2 N.
The force is applied 0.25 m from the pivot.
(a) (i) State the equation linking moment, force and
distance. (1)
(ii) Calculate the moment of the force that opens the
computer. (2)
Moment = ........................................................................................................
N m
(b)
The student finds that 4.2 N is the minimum
upward force needed to open the
computer.
Then the student applies a downward
force, F, to close the computer.
Explain why the minimum force needed to close the computer is
likely to be less
than 4.2 N.
(2)
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2. A train travels 9 km from station A to station
B. It takes 15 minutes.
(a)
(i) State the equation
linking average speed, distance moved and time taken. (1)
(ii) Calculate the average speed of the train and give its
unit. . (3)
Average speed = ..................................................
unit ..................................................
(iii) The maximum speed of the train must be higher than the value
you have
calculated.
Explain why. (2)
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(b)
The train continues along a straight track from station B to station C.
The
graph shows how the velocity of the train changes with time during this part of
the
journey.
(i) Use the graph to calculate the acceleration of the train, in
m/s2, during the first
100 seconds after it leaves station B. (3)
Acceleration = ..............................................................
m/s2
(ii) Use the graph to calculate the distance, in m, between station
B and station C. (3)
Distance = ..............................................................
m
3.
Scientists test the safety
features of a car by crashing it into a large block of concrete.
A dummy is placed in the driver’s seat and the scientists video
the crash.
(a) In one test, the dummy and the car travel at 8 m/s. The mass
of the dummy is 72 kg. Calculate the momentum of the dummy. (2)
Momentum = ....................................................
kg m/s
(b) In another test, the momentum of the dummy changes by 920 kg
m/s in a time of 0.17 s.
Calculate the average horizontal force acting on the dummy during
this time. (2)
Average force = ....................................................
N
(c) These tests help to make our roads safer.
(i) State two factors that affect the
stopping distance of a car driven on a road.
(2)
1................................................................................................................................................................................................................................................................................................................................................................................
2................................................................................................................................................................................................................................................................................................................................................................................
(ii) Use ideas about momentum to explain how the crumple zone of a
car helps to reduce injuries during a crash.
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4.
A rabbit runs across the road in front of a car.
The driver applies
the brakes.
State four factors
that affect the chance of the rabbit escaping without being hit. (4)
1................................................................................................................................................................................................................................................................................................................................................................................
2................................................................................................................................................................................................................................................................................................................................................................................
3................................................................................................................................................................................................................................................................................................................................................................................
4................................................................................................................................................................................................................................................................................................................................................................................
5.
Photograph C shows a student using an old camera that uses
film.
Photograph C
(a) The film is pulled
through the camera using lever A.
The student pushes on lever
A with a force of 7.0 N.
The force is applied 0.04 m
from the pivot.
(i) State the equation
linking moment, force and distance. (1)
(ii) Calculate the
moment of the force that turns lever A and give the unit. (3)
Moment =
.................................................. unit
..................................................
(b) When all the film
has been used, it is pulled back through the camera using lever R.
Photograph D
The force acting on
lever R is only 0.02 m from its pivot.
Explain why the
minimum force needed to turn lever R is likely to be more than 7 N. (2)
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6.
(a) Parachutes are used to slow down a spacecraft as it falls
through the atmosphere.
Photograph G shows
an Apollo spacecraft with three parachutes attached.
Photograph G
This spacecraft falls
at a constant velocity.
(i) State the name of
this constant velocity.(1)
.........................................................................................................................................................................................
(ii) Explain why this
velocity stays at a constant value.(3)
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(iii)
Photograph H shows an
identical Apollo spacecraft. Only two of its parachutes are working.
Photograph H
Explain how the
constant velocity reached by this spacecraft compares with
the constant velocity
of the spacecraft shown in photograph G.(2)
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(b)
Photograph I shows a Space Shuttle using a parachute when it lands on a
runway.
Explain what would
happen to the stopping distance of the Shuttle if this parachute did not open. (2)
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7. The diagram shows
the driving force on a sports car as it moves along a race track.
(a) Name two forces that oppose the driving force.(2)
1 .........................................................................................................................................................................................
2
.........................................................................................................................................................................................
(b) The car has a
mass of 1400 kg. The acceleration of the car is 5.5 m/s2.
(i) State the
equation linking force, mass and acceleration. (1)
(ii) Calculate the
force causing this acceleration. (2)
Force =
........................................... N
Calculate the distance that the car travels in the first four
seconds.(3)
Distance
= ...........................................
m
(d) As the car travels further along the track, its acceleration
changes as shown in graph 2.
(i) Which feature of
graph 2 shows that the acceleration changes?(1)
.........................................................................................................................................................................................
(ii) The acceleration
changes even though the driving force does not change.
Suggest two possible
reasons for this change in acceleration.(2)
1
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2
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