Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physics > Section 7: Further Mechanics > Flashcards

Section 7: Further Mechanics Flashcards

1
Q

How do convert the angle in radians to an angle in degrees?

A

angle in radians = angle in degrees x pi/180

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is angular speed?

A

The angle an object rotates through per second

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is linear speed also known as?

A

tangential speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the frequency in circular motion?

A

the number of complete revolutions per second

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the unit for frequency in circular motion?

A

hertz (Hz) or rev/s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the period in circular motion?

A

The time taken for a complete revolution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the unit for period in circular motion?

A

seconds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do we know that there must be a centripetal acceleration within circular motion?

A

Objects travelling in circles are accelerating since their velocity is changing. Even if the car is going a constant speed, its velocity is changing since its direction is changing. Since acceleration is defined as the rate of change of velocity, the object is accelerating even though it isn’t going any faster. This acceleration is called the centripetal acceleration.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

In which direction is the centripetal acceleration directed?

A

towards the centre of the circle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do we know that there is a centripetal force?

A

Newton’s first law of motion says that an object’s velocity will stay the same unless there is a force acting on it. Since an object travelling in a circle has a centripetal acceleration, there must be a force causing this acceleration. This force is called the centripetal force.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

In which direction does the centripetal force act?

A

towards the centre of the circle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Does the centripetal force or centripetal acceleration have a larger magnitude?

A

force has a bigger magnitude due to F=ma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the centripetal force?

A

It is the resultant force that is keeping the body moving in a circle. It can be sometimes be one of the components of a force.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the 3 types of circle?

A

1 horizontal
2 vertical
3 conical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the definition of simple harmonic motion?

A

It is a vibration about a fixed point where the acceleration is directly proportional to the displacement.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the displacement in simple harmonic motion?

A

The distance of the object from the equilibrium position

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What kind of force is always present in a simple harmonic motion system?

A

There is always a restoring force pulling or pushing the object back towards the equilibrium position. The size of the restoring force depends on the displacement. The restoring force makes the object accelerate towards the equilibrium.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the maximum value of displacement in SHM?

A

the amplitude of the system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How can you find the velocity of a SHM system using a displacement-time graph?

A

velocity is the gradient of the displacement-time graph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How can you find the acceleration of a SHM system using a velocity-time graph?

A

acceleration is the gradient of the velocity-time graph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is phase difference?

A

It is a measure of how much one wave lags behind another wave, and can be measured in radians, degrees, or fractions of a cycle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How do you know when two waves are in phase with each other?

A

Two waves that are in phase with each other have a phase difference of 0 (or 2 pi radians).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How do you know when two waves are exactly out of phase with each other?

A

If two waves are exactly out of phase (in antiphase), they have a phase difference of pi radians or 180 degrees - one wave’s maximum occurs at the same time as the other’s minimum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is one cycle of SHM oscillation in terms of displacement?

A

From maximum positive displacement (e.g. maximum displacement to the right) to maximum negative displacement (e.g. maximum displacement to the left) and and back again

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the amplitude of a SHM oscillation?

A

The maximum magnitude of the displacement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What does the type of potential energy of a SHM motion depend on?

A

The type of potential energy depends on what is providing the restoring force for the system.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What provides the restoring force for a SHM pendulum system?

A

gravitational potential energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What provides the restoring force for a SHM spring system?

A

elastic strain energy or gravitational potential energy for the masses on springs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

How does energy vary throughout an oscillation of a SHM system?

A

1 As the object moves towards the equilibrium position, the restoring force does work on the object and so transfers some potential energy to kinetic energy.
2 When the object is moving away from the equilibrium, all the kinetic energy is transferred back the potential energy again.
3 At the equilibrium, the object’s potential energy is said to be 0 and the kinetic energy is at a maximum - therefore its velocity is maximum
4 At the maximum displacement on both sides of the equilibrium, the object’s potential energy is maximum and the kinetic energy is 0 - so its velocity is 0.

30
Q

When an object is moving towards the equilibrium in a SHM system, how does energy change?

A

As the object moves towards the equilibrium position, the restoring force does work on the object and so transfers some potential energy to kinetic energy.

31
Q

When an object is moving away from the equilibrium in a SHM system, how does energy change?

A

When the object is moving away from the equilibrium, all the kinetic energy is transferred back the potential energy again.

32
Q

When an object is at the equilibrium of a SHM system, what is the energy like?

A

At the equilibrium, the object’s potential energy is said to be 0 and the kinetic energy is at a maximum - therefore its velocity is maximum

33
Q

When an object at at the amplitude of a SHM system, what is the energy like?

A

At the maximum displacement on both sides of the equilibrium, the object’s potential energy is maximum and the kinetic energy is 0 - so its velocity is 0.

34
Q

What is the sum of the potential energy and kinetic energy called?

A

mechanical energy/ total energy

35
Q

How does mechanical/total energy change during an oscillation in a SHM system?

A

it remains constant

36
Q

What is a mass on a spring in a SHM system called?

A

Simple harmonic oscillator

37
Q

What does SHO stand for?

A

simple harmonic oscillator

38
Q

Using a mass-spring SHM system, if you doubled k, what would happen to w?

A

Doubling k (with the same m) would increase w by a factor of root 2

39
Q

What is a simple pendulum?

A

One where the amplitude never decreases (we do NOT consider air resistance)

40
Q

What is the SHM practical that uses a mass-spring system?

A

Attach a trolley to a spring, pull it to one side by a certain amount and then let go. The trolley will oscillate back and forth as the spring pulls and pushes it in each direction. You can measure the period (T) by getting a computer to plot a displacement-time graph from a data logger connected to a position sensor.

41
Q

During the SHM practical using a mass-spring system, how is the variable of mass used?

A

Change the mass, m, by loading the trolley with mass - don’t forget to include the mass of the trolley in the calculations. Since T is directly proportional to the root of m, the square of T should be proportional to the mass.

42
Q

During the SHM practical using a mass-spring system, how is the variable of the spring constant used?

A

Change the spring constant, k, e.g. by using different combination of springs. The square of T should be proportional to the inverse of the spring constant

43
Q

During the SHM practical using a mass-spring system, how is the variable of the amplitude used?

A

Change the amplitude by pulling the trolley across by different amounts. Since T doesn’t depend on amplitude, there should be no change in the period.

44
Q

What is the SHM practical that uses a simple pendulum?

A

You can use a simple pendulum attacked to an angle sensor and computer to test the equation for the time period of a pendulum. Use the computer to plot a displacement-time graph and read off the period, T, from it. Make sure you calculate the average period over several oscillations to reduce the percentage error in your measurement.
You can also do this experiment by hanging the pendulum from a clamp and timing the oscillations using a stop-watch. Mark a reference point to tell when the pendulum has reached the mid-point of its oscillation.

45
Q

How does a U-tube containing water show SHM?

A

When at equilibrium, the levels of the water on either side of the tube are equal. When the water is pushed down on one side of the tube, the water level on the opposite side rises. When the pressure is then released, the water undergoes SHO, as the water levels on each side rise and fall.

46
Q

What calculations can you complete using the SHM system of the U-tube containing water?

A

The setup has the water in the U-tube that has density, volume, cross-sectional area and length. As the water oscillates, it will exchange kinetic and potential energy. At equilibrium position (when the water levels are aligned), the kinetic energy will be at a maximum and the potential energy will be 0. At the maximum displacement, potential energy will be at its maximum and kinetic energy will be 0. Using conservation of mechanical energy and assuming that friction is negligible, the change in kinetic energy is equal to the change in the potential energy.

47
Q

What are free vibrations?

A

They involve no transfer of energy to or from the surroundings.

48
Q

What happens is you stretch and release a mass on a spring?

A

It oscillates at its resonant frequency (or natural frequency).

49
Q

What are forced vibrations?

A

They happen when there’s an external driving force. A system can be forced to vibrate by periodic external force.

50
Q

What is the driving frequency?

A

The frequency of a periodic external force that forced a system to vibrate .

51
Q

What happens if the driving frequency is much less than the natural frequency?

A

The two was in phase

52
Q

What happens if the driving frequency is much greater than the natural frequency?

A

The oscillator won’t be able to keep up - you end up with the driver completely out of phase with the oscillator (in antiphase).

53
Q

How do you know when a system is resonating?

A

When a driving frequency approaches the natural frequency, the system gains more and more energy from the driving force and so vibrates with a rapidly increasing amplitude.

54
Q

At resonance, what is the phase difference between the driver and the oscillator?

A

90 degrees

55
Q

What is damping?

A

In practice, any oscillating system loses energy to its surroundings. This is usually down to frictional forces like air resistance.

56
Q

What are the frictional forces that cause damping called?

A

dissipative forces

57
Q

What are the damped harmonic motion?

A

1 amplitude decreases
2 Time period is constant throughout the motion
3 Decay of A is exponential

58
Q

How do you show that the decrease in amplitude in damped harmonic motion is exponential?

A

Find ratios of consecutive amplitude and check if they are the same.

59
Q

What are the 4 types of damped harmonic motion?

A

1 lightly damped
2 heavily damped
3 critically damped
4 overdamping

60
Q

What is harmonic motion that is lightly damped?

A

They take a long time to stop oscillating, and their amplitude only reduces by a small amount each period.

61
Q

What are harmonic motion that is heavily damped?

A

It takes less time to stop oscillating and their amplitude gets much smaller each period

62
Q

What is an example of a lightly damped harmonic motion?

A

small bob pendulum

63
Q

What is an example of a heavily damped harmonic motion?

A

large bob pendulum

64
Q

What is harmonic motion that is critically damped?

A

The amplitude reduces to 0 in the shortest possible time

65
Q

What is an example of critically damped harmonic motion?

A

Car suspension systems are critically damped so that they don’t oscillate but return to equilibrium as quickly as possible

66
Q

What is harmonic motion that is overdamped?

A

Systems with even heavier damping are overdamped. They take longer to return to equilibrium than a critically damped system.

67
Q

What is an example of harmonic motion that is overdamped?

A

Some heavy doors are overdamped, so that they don’t slam shut too quickly, but instead close slowly, giving people time to walk through them.

68
Q

How is plastic deformation linked to damping of harmonic motion?

A

Plastic deformation of ductile materials reduces the amplitude of oscillations in the same way as damping. As the material changes shape, it absorbs energy, as the oscillation will be smaller.

69
Q

What is the resonance of a lightly damped harmonic motion system?

A

Lightly damped systems have a very sharp resonance peak. Their amplitude only increases dramatically when the driving frequency is very close to the natural frequency.

70
Q

What is the resonance of a heavily damped harmonic motion system?

A

Heavily damped systems have a flatter response. Their amplitude doesn’t increase very much near the natural frequency and they aren’t as sensitive to the driving frequency.

71
Q

What is an application of a system that has bee critically damped?

A

Some structures are damped to avoid being damaged by resonance. Some buildings in regions prone to earthquakes have a large mass called a tuned mass damped. When an earthquake causes the building to shake, the mass moves in the opposite direction to the building, damping its oscillation.

72
Q

What experiment can be used to demonstrate the effect of damping on the resonance of a spring-mass system?

A

A flat disc is attached to the set-up. As the mass oscillates, air resistance on the disc acts as a damping force, reducing the amplitude of the oscillation. The larger the disc, the larger the damping force and the smaller the amplitude of the oscillation of the system at resonance.

Physics (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions