Physics Paper 2 Flashcards
What is the main difference between scalar and vector quantities?
Vectors quantities have a magnitude and direction, but scalar quantities only have a magnitude.
Vector quantities may be represented by an arrow, describe how.
The length of the arrow can represent the magnitude, and the direction the arrow is pointing can represent the direction of the vector quantity.
State 3 vector quantities.
Any three from: force, velocity, acceleration, momentum, displacement
State 3 scalar quantities.
Any three from: time, distance, speed, mass, temperature.
Complete the sentence: “A force is a __________ or ____________ that acts on an object due to the ________________ with another object.”
Push, pull, interaction.
State the condition required for a contact force to occur.
Two objects have to be touching.
Other than contact forces, what other type of forces are there?
Non-contact forces.
State 2 contact forces.
Any two from: friction, air resistance, tension in ropes, normal contact force.
State 2 non-contact forces.
Any two from: magnetic force, gravitational force, electrostatic force.
Is force a vector or scalar quantity, why?
It is a vector quantity because it has a magnitude and direction.
Describe the pair of forces that exist between a chair resting on the ground.
The chair exerts a force on the ground, while the ground pushes back at the chair with the same force. The forces are equal but opposite.
If two objects are interacting with forces that are equal but opposite, how would the forces be represented by arrows?
The arrows would be equal in length and pointing in opposite directions.
What is weight?
A force acting on an object due to gravity.
State the equation that links weight, mass and gravitational field strength.
weight = mass x gravitational filed strength
What are the units of weight?
Newtons, N
What units of mass are used in physics equations?
kilograms, kg
What are the units of gravitational field strength?
N/kg
What is meant by the term “centre of mass”?
A single point at which you can assume the mass is concentrated, and where the weight of an object is acting upon.
Name the piece of equipment that can be used to measure weight.
A newton meter.
What is the mass of a book which has a weight of 5.37 N on Earth where g = 9.8 N/kg?
5.37 / 9.8 = 0.55kg
What is the mass of a book which has a weight of 2.07 N on Earth where g = 9.8 N/kg?
2.07 / 9.8 = 0.21kg
What is the weight of a book which has a mass of 0.0881 kg on Earth where g = 9.8 N/kg ?
0.0881 x 9.8 = 0.86N
What is the weight of a book which has a mass of 0.790 kg on Earth where g = 9.8 N/kg ?
0.79 x 9.8 = 7.742N
What is the mass of a book which has a weight of 0.524 N on Venus where g = 8.8 N/kg?
0.524 / 8.8 = 0.06kg
What is the weight of a book which has a mass of 0.355 kg on Mercury where g = 3.6 N/kg ?
0.355 x 3.6 = 1.278N
What is a resultant force?
It is when a single force is used to replace a number of forces acting on an object.
A car has two forces acting on it. 20N east and 45N west. Calculate the resultant force.
25N west.
A car has two forces acting on it. 34N east and 12N west. Calculate the resultant force.
22N east.
State the equation that links work done, force and distance.
Work done = force x distance
What other phrase can be used instead of work done?
Energy transferred.
What are the units of work done?
J or Nm
Convert 15J to Nm
15Nm
Covert 34.6 Nm to J
34.6J
When work is done against frictional forces what happens to the temperature of the object?
It increases.
A force is applied to a box and does 4190 J of work, causing the box to move 51.4 m in the direction of the force. Calculate the size of the force.
4190 / 51.4 = 81.52N
A force is applied to a box and does 4930 J of work, causing the box to move 58.6 m in the direction of the force. Calculate the size of the force.
4930 / 58.6 = 84.13N
A force of 96.0 N is applied to a box, causing the box to move 93.4 m in the direction of the force. How much work was done moving the box?
96 x 93.4 = 8966.4J
A force of 28.2 N is applied to a box, causing the box to move 80.1 m in the direction of the force. How much work was done moving the box?
28.2 x 80.1 = 2258.82J
A force of 16.0 N is applied to a box and causes it to move in the direction of the force. The force does 1580 J of work moving the box. Calculate the distance the box moves.
1580 / 16 = 98.75m
A force of 72.6 N is applied to a box and causes it to move in the direction of the force. The force does 2370 J of work moving the box. Calculate the distance the box moves.
2370 / 72.6 = 32.64m
How many forces must be acting on an object in order for it to stretch, compress or bend?
2 or more
Give an example of when forces cause an object to stretch.
When you stretch an elastic band.
Describe what happens to an object if it only has one force acting on it.
It would move in the direction of the applied force.
What does the term “elastically deformed” mean?
When an object that has been stretched can revert back to its original shape and length after the forces have been removed.
What does the term “inelastically deformed” mean?
When an object that has been stretched can’t revert back to its original shape and length after the forces have been removed.
Complete the following sentence: “The extension of an elastic object, such as a spring, is _________ _________________ to the force applied, provided that the limit of ______________________ is not exceeded.”
Directly, proportional, proportionality
State the equation that links force, spring constant and extension.
force = spring constant x extension
State the units of spring constant.
N/m
A spring has a spring constant of 61.4 N/m. A force of 30.5 N is applied to it to stretch the spring. Calculate the extension of the spring.
30.5 / 61.4 = 0.50m
A spring has a spring constant of 151 N/m. A force of 139 N is applied to it to stretch the spring. Calculate the extension of the spring.
139 / 151 = 0.92m
A spring is 0.954 m long when unstretched. A force of 2.02 N is applied to the spring to stretch it to a length of 1.141 m. Calculate the spring constant of the spring.
- 141 - 0.954 = 0.187
2. 02 / 0.187 = 10.8 N/m
A spring is 1.90 m long when unstretched. A force of 8.69 N is applied to the spring to stretch it to a length of 1.9591 m. Calculate the spring constant of the spring.
- 9591 - 1.9 = 0.0591
8. 69 / 0.0591 = 147.04 N/m
A spring is 0.833 m long when unstretched and has a spring constant of 88.1 N/m. Calculate the force required to stretch the spring to a length of 1.697 m.
- 697 - 0.833 = 0.864
88. 1 x 0.864 = 76.12N
A spring is 0.564 m long when unstretched and has a spring constant of 75.8 N/m. Calculate the force required to stretch the spring to a length of 1.248 m.
- 248 - 0.564 = 0.684
75. 8 x 0.684 = 51.85N
When forces cause an object to stretch or compress, which energy store gains energy?
Elastic potential energy store.
Define distance.
How far an object has moved.
Define displacement.
Displacement includes both the distance an object moves, measured in a straight line from the start point to the finish, and the direction of that straight line.
Describe the difference between distance and displacement.
Distance is a scalar quantity and only has a magnitude, whereas displacement is a vector quantity and has magnitude and direction.
Is distance a scalar or vector quantity?
Scalar
Is displacement a distance or vector quantity?
Vector
Is speed a scalar or vector quantity?
Scalar
What is the typical speed of a person walking?
1.5m/s
What is the typical speed of a person running?
3m/s
What is the typical speed of a person cycling?
6m/s
What is the typical speed of a moving car?
25m/s
What is the typical speed of a moving train?
30m/s
What is the typical speed for a moving aeroplane?
250m/s
What is the typical speed for sound in air?
330m/s
State the equation that links speed, distance travelled and time.
distance travelled = speed x time
What are the units of speed?
m/s
A cyclist travels 63.5 m in 5.73 s. What was their average speed?
63.5 / 5.73 = 11.08 m/s
A cyclist travels 78.2 m in 8.78 s. What was their average speed?
78.2 / 8.78 = 8.91 m/s
A cyclist has a speed of 6.89 m/s and travels for 8.05 s. How far did they travel?
6.89 x 8.05 = 55.47 m
A cyclist has a speed of 5.31 m/s and travels for 9.61 s. How far did they travel?
5.31 x 9.61 = 51.03 m
A cyclist has a speed of 14.4 m/s. How long does it take them to travel 95.9 m?
95.9 / 14.4 = 6.66 s
A cyclist has a velocity of 8.91 m/s. How long does it take them to travel 78.2 m?
78.2 / 8.91 = 8.78 s
Is velocity a scalar or vector quantity, why?
It is a vector quantity because it has a magnitude and direction.
Define velocity.
Speed in a given direction.
A car is going around a roundabout at 25m/s. Explain why it has a constant speed, but its velocity is constantly changing.
It has a constant speed because it is travelling at a steady 25m/s. Its velocity is constantly changing because it is constantly changing direction. Velocity has magnitude and direction whereas speed only has magnitude.
For a distance time graph, how can the speed of an object be calculated?
By calculating the gradient of the line.
For a distance time graph, what does a straight section show?
The object is stationary.
For a distance time graph, what does an upwards curve show?
The object is accelerating.
For a distance time graph, what does a slope show?
The object is travelling at a steady speed.
From a distance time graph, how can you determine the speed at any particular time?
By drawing a tangent and measuring the gradient of the line.
State the equation that links acceleration, change in velocity and time taken.
acceleration = change in velocity / time taken
State the units of acceleration.
m/s2
Complete the sentence: “An object that slows down is __________.”
Decelerating.
For a velocity time graph, how can the acceleration of an object be calculated?
By calculating the gradient of the line.
For a velocity time graph, what does a straight line show?
The object has a constant acceleration.
For a velocity time graph, what does a flat section show?
The object is travelling at a steady speed.
For a velocity time graph, what does an upwards curve show?
The object’s acceleration is increasing.
For a velocity time graph, how can you determine the distance travelled by an object?
By calculating the area under a velocity-time graph.
A train initially travelling at 58.9 m/s accelerates at 4.93 m/s² and reaches a final velocity of 96.9 m/s. How long was the train accelerating for?
96.9 - 58.9 = 38
38/ 4.93 = 7.71 s
A train initially travelling at 50.5 m/s accelerates at -5.60 m/s² and reaches a final velocity of 23.4 m/s. How long was the train accelerating for?
- 4 - 50.5 = -27.1
- 27.1 / -5.6 = 4.84 s
A train accelerates from an initial velocity of 91.5 m/s to a final velocity of 23.2 m/s in a time of 9.64 s. What is the acceleration of the train?
- 2 - 91.5 = -68.3
- 68.3 / 9.64 = -7.09 m/s2
A train accelerates from an initial velocity of 58.9 m/s to a final velocity of 96.9 m/s in a time of 7.71 s. What is the acceleration of the train?
96.9 - 58.9 = 38
38 / 7.71 = 4.93 m/s2
A train travelling at 80.1 m/s accelerates at -9.10 m/s² for 3.34 s. What is the final velocity of the train?
- 34 x -9.1 = -30.394
80. 1 - 30.394 = 49.71m/s
A train accelerates at 1.44 m/s² for 7.70 s until it reaches a final velocity of 94.5 m/s. What was the initial velocity of the train?
- 44 x 7.7 = 11.088
94. 5 - 11.088 = 83.41 m/s
A motorbike accelerates at 9.82 m/s² from an initial velocity of 32.7 m/s to a final velocity of 76.3 m/s. Calculate the distance travelled.
- 32 - 32.72 = 2 x 9.82 x s
- 4 = 19.64 x s
- 4 / 19.64 = s
- 98m
A motorbike travels 223 m whilst accelerating from an initial velocity of 36.8 m/s to a final velocity of 68.7 m/s. What was the acceleration of the motorbike?
- 72 - 36.82 = 2 x a x 223
- 45 = 446 x a
- 55 m/s2
A motorbike travels 179 m whilst accelerating at 1.62 m/s² and ends up with a velocity of 31.2 m/s. What was the initial velocity of the motorbike?
31.22 - u2 = 2 x 1.62 x 179
973.44 - u2 = 579.96
-u2 = 579.96 - 973.44
-u2 = -393.48
u = √393.48
u = 19.8 m/s
A motorbike is initially travelling at 20.4 m/s and accelerates at 7.23 m/s² whilst travelling 209 m. What is the final velocity of the motorbike?
v2 - 20.42 = 2 x 7.23 x 209 v2 -416.16 = 3022.14 v2 = 3022.14 + 416.16 v2 = 3438.3 v = √3438.3 v = 58.6 m/s
Complete the following sentence: “If an object has no force propelling it along, it will always ________ down and ________________, because of ____________.”
Slow, stop, friction.
When do frictional forces occur?
When two surfaces are in contact, or when an object passes through a fluid.
What are fluids?
A gas or liquid.
What is drag?
It is a resistive force you get in fluids.
What is air resistance?
It is a type of drag that occurs in air
How could you decrease the drag experienced by a race car?
Make it more streamlined.