Past Paper Qs (CORE PHYSICS 1, Booklet 1) Flashcards
An experiment is carried out to find a value for g (acceleration of free fall).
A dowel of known length l is dropped through two light gates. By inputting the length of the card into a computer the two values of velocity and time interval between light gates can be obtained.
Assuming air resistance is negligible, which of the following would produce a more reliable value of g ?
A- drop the card from a greater height
B- ensure card is dropped from rest
C- make card shorter
D- move light gates further apart
D- move light gates further apart
Two wires of the same material are connected in series with each other. Wire A has twice the diameter of wire B. In which of the following are both correct?
current in wire A/ current in wire b Drift speed in wire A/Drift speed in wire B
A = 1 1/4
B = 1 4
C = 2 4
D = 2 1/4
A- 1 and 1/4
A steady potential difference is applied across a variable resistor that is kept at a constant temperature
The graph which represents the relationship between the resistance R of the variable resistor and the current I through it is
A
The graph is a displacement-time graph for a runner.
The velocity of the runner at 5s is approximately:
A- 8ms^-1
B- 9ms^-1
C- 12ms^-1
D- 40ms^-1
C- 12ms^-1
A child goes down a slide. Which of the diagrams correctly represents the forces acting on the child?
A
A box is dropped from a plane flying at a constant velocity and height.
Assuming that air resistance is negligible, as the box falls to the ground its horizontal position will…
A- remain unchanged
B- lag behind the plane
C- move ahead of the plane
D- remain directly under the plane
D- remain directly under the plane
A car battery has an e.m.f of 12V and an internal resistance of 3.0 x 10^-3 ohms. For the starter motor to turn the engine, the battery must provide a current of 400 A.
a) calculate the terminal potential difference across the terminals of the battery when the current through the battery is 400A. (3)
V = 12 - ( 3 x 10^-3)x 400
= 10.8 V
A car battery has an e.m.f of 12V and an internal resistance of 3.0 x 10^-3 ohms. For the starter motor to turn the engine, the battery must provide a current of 400 A.
(b) the copper wires between the battery and the motor have a diameter of 1cm.
Explain why such a thick wire is needed. (3)
. Prevents the wire heating up
. As there is a large pd (voltage) across the wires
To allow a large current
.Resistance of cable is low (as cross sectional area is large)
A student uses a camera to video the movement of a toy, as it bounces, in front of a metre rule.
The video is then used to find the maximum height reached by the toy.
(i) Explain the advantage of using the video camera over using observations just by eye. (2)
. Improves accuracy/ reliability/ precision
. Eliminates reaction time in looking (can slow down + stop vid)
- You’re asked to determine the acceleration of free fall at the surface of the earth, g, using a free fall method in the laboratory.
(a) Describe the apparatus you would use, the measurements you would take and explain how you would use them to determine g. (6)
. State quantities to be measured (e.g. s and t OR v, u and t OR u,v and s)
. Relevant apparatus ( ruler and timer/ data logger/ light gates)
. Describe how distance is measured
. Describe how speed or time is measured
. Further detail of measurement of speed or time
. Vary for described quantities + plot appropriate graph
. State how result calculated
. Repeat and mean
Different countries supply mains electricity at different voltages. Many hotels now offer a choice of voltage supplies as shown in photo.
(i) By mistake, the kettle is connected to the 110V supply. Assuming that the working resistance of the kettle doesn’t change, calculate the time it would take for the same amount of water to reach boiling point (3)
Power= 250 W
Time = 720 s
The graph shows the amount of carbon dioxide emitted per kilometre by a typical car at different speeds.
During a 10 minute journey a cyclist, travelling at 5ms^-1, has an average of three cars queuing behind him. The cars would otherwise be travelling at 18ms^-1. The cars emit more carbon dioxide because they are travelling slowly.
(i) Calculate the extra carbon dioxide emitted by the 3 cars due to travelling at this reduced speed for ten minutes (4)
. Use of distance = speed x time (3km)
. Use of emission = distance x reading from graph
. Use of difference between emissions at different speeds for 1 or 3 cars
CO2 emissions= 0.72kg
E.g distance = 5m/s x 10 x 60s= 3000m or 3km
3 x 3km x( 0.26kg/km - 0.18kg/km)= 0.72kg
The photograph shows an athlete performing a long jump.
At take-off his horizontal speed is 8.0ms^-1 and his vertical speed is 2.8ms^-1
(c) In reality , when the athlete land his centre of gravity is 50cm lower than its position at take-off.
Calculate the extra horizontal distance this enables the athlete to jump. (4)
v^2= (2.8m/s)^2 + (2 x 9.81m/s^2 x 0.50 m)
v = 4.2m/s
t = 4.2m/s - 2.8m/s
———————
9.81m/s^2
t = 0.14s
Distance = speed x time
= 8m/s x 0.14s
= 1.1m
- a projectile would have a grater range on the moon than on the earth because of the lower gravitational field strength and because of the lack of an atmosphere.
Explain how each of these factors would increase the range of the projectile. (3)
. Lower gravitational field strength
- lower acceleration
- idea of an increased time of flight
. Lack of atmosphere
- no work done against friction (air resistance)
*(b) The diagram hows three positions of the kite when pulling the surfer along.
State and explain which position of the kite would supply the most power to the surfer.
Assume that the tension in the kite lines is the same in each position. (4)
. C
. The horizontal component of the tension in the line produces the forward force acting on the surfer.
. As the angle to the horizontal decreases, forward force on the surfer increases
. Work done increases
. Power transferred to the surfer= work done
—————
Time
More work done per second so power increases
The diagram shows a circuit set up by a student.
(a) Both voltmeters have a resistance of 10 Mohms. The reading on V1is 6V and the reading on V2 is zero.
Explain these readings. (2)
. Resistance of parallel combination is much less than resistance of V1,
. Therefore voltage of parallel combination is much less than voltage of V1.
OR
. Current is nearly zero because of resistance in V1 being so large
. So voltage across 10 ohms is zero by V=IR
The diagram shows a circuit set up by a student.
(b) The student replaces the 10 ohm resistor with one of unknown resistance R. The reading on V1 is now 4V.
Calculate R. (3)
. Parallel combination resistance = 5M ohms
(use of resistors in parallel formula)
. R= 10M ohms
