Kinematics + Mechanics I: Force, Work, Energy Flashcards Preview

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Flashcards in Kinematics + Mechanics I: Force, Work, Energy Deck (64)
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1
Q

Definition of Speed

A

Rate of change of distance

2
Q

Speed - What type of Physical Quantity?

A

Scalar

3
Q

Speed - Formula

A

Speed = distance/time

4
Q

Definition of Velocity

A

Rate of change of Displacement

5
Q

Velocity - What type of Physical Quantity?

A

Vector

6
Q

Velocity - Formula

A

Velocity = Displacement/time

7
Q

Calculation of Average Speed (in a changing speed route)?

A

Average Speed = Total Distance travelled / Total Time

8
Q

What is the definition of Acceleration?

A

Acceleration is the rate of change of velocity.

9
Q

What is the SI Unit of Acceleration?

A

Acceleration SI Unit - m/s^2

10
Q

Acceleration is a _____ quantity.

A

Acceleration is a VECTOR quantity.

11
Q

The direction of acceleration is the direction of ______ __ ______.

A

The direction of acceleration is the direction of CHANGE IN VELOCITY.

12
Q

There is acceleration only when velocity _______ !

A

There is acceleration only when velocity CHANGES!

13
Q

If velocity is constant throughout, there is no _________!

A

If velocity is constant throughout, there is no ACCELERATION!

14
Q

If the velocity is decreasing, then the object is said to have ___________.

A

If the velocity is decreasing, then the object is said to have DECELERATION.

15
Q

What does it mean when we say - uniform acceleration?

A

Uniform Acceleration : Acceleration that is constant (same value).

16
Q

What does it mean when we say - non-uniform acceleration?

A

Uniform Acceleration : Acceleration that is changing (Increasing/Decreasing Value)

17
Q

Describe - How would a “ object at rest”, distance over time graph look like?
(Theses are kinematic Patterns that are useful to remember)

A

Since the distance value doesn’t change - Horizontal Line Parallel to the time (x Axis).
(Try to draw it if it doesn’t add up)

18
Q

Describe - How would a “object with Uniform Velocity”, distance over time graph look like?
(Theses are kinematic Patterns that are useful to remember)

A

A steep line going upwards with a slope that is equal to the velocity of the moving object.
(Try to draw it if it doesn’t add up)

19
Q

Describe - How would a “Object with Uniform Acceleration”, distance over time graph look like?
(Theses are kinematic Patterns that are useful to remember)

A

A curved line bent upwards - since there is an increase in velocity the rate of distance from the moving object keeps growing faster and faster.
(Try to draw it if it doesn’t add up)

20
Q

Describe - How would a “Object with Uniform Deceleration”, distance over time graph look like?
(Theses are kinematic Patterns that are useful to remember)

A

A curved line bent downwards - since there is a decrease in velocity the rate of distance from the moving object grows slower and slower. This could reach a point similar to the “at rest” graph where distance is constant!
(Try to draw it if it doesn’t add up)

21
Q

Describe - How would a “ object at rest”, speed over time graph look like?
(Theses are kinematic Patterns that are useful to remember)

A

No line. No movement = Speed is equal to zero .
At any point in time there is no speed - mathematically meaning that no value on the x axis will produce a value for the y axis.

22
Q

Describe - How would a “ Object with Uniform Velocity”, speed over time graph look like?
(Theses are kinematic Patterns that are useful to remember)

A

Since the speed value doesn’t change - Horizontal Line Parallel to the time (x Axis).
(Try to draw it if it doesn’t add up)

23
Q

Describe - How would a “ Object with Uniform Acceleration”, speed over time graph look like?
(Theses are kinematic Patterns that are useful to remember)

A

A steep line going upwards. Since there is a constant increase in velocity it has a slope that is equal to the acceleration value.
(Try to draw it if it doesn’t add up)

24
Q

Describe - How would a “ Object with Uniform Deceleration”, speed over time graph look like?
(Theses are kinematic Patterns that are useful to remember)

A

A steep line going downwards. Since there is a constant decrease in velocity it has a slope that is equal to the deceleration value.
(Try to draw it if it doesn’t add up)

25
Q

Describe - How would a “Object with Increasing Non-Uniform Acceleration”, velocity over time graph look like?
(Theses are kinematic Patterns that are useful to remember)

A

A curved line bent upwards - since there is an increase in velocity that grows faster and faster. The value of the velocity becomes greater in an increasing rate!
(Try to draw it if it doesn’t add up)

26
Q

Describe - How would a “Object with Increasing Non-Uniform Deceleration”, velocity over time graph look like?
(Theses are kinematic Patterns that are useful to remember)

A

A curved line bent downwards- since there is a decrease in velocity that grows slower and slower. The value of the velocity becomes smaller in a decreasing rate! This could reach a point where the value of the velocity is constant (or zero) - Horizontal line over the x axis.
(Try to draw it if it doesn’t add up)

27
Q

What is the meaning of the area under the curve for a Velocity over time graph?
(Hint: Integral of speed function)

A

Displacement

28
Q

What is the meaning of the slope/gradient of the curve for a Velocity over time graph?
(Hint: Derivative of speed function)

A

Acceleration

29
Q

What is the meaning of the area under the curve for a Acceleration over time graph?
(Hint: Integral of acceleration function)

A

Velocity

30
Q

What is the meaning of the slope/gradient of the curve for a Displacement over time graph?
(Hint: Derivative of Displacement function)

A

Velocity

31
Q

What is the acceleration value of an object in free fall? What is this value called?
(No air resistance/friction)

A

Gravitation/Earth constant = 10 ~ (m/s^2)

32
Q

Any object that is being acted upon only by the force of gravity is said to be in a state of ___ _____.

A

Any object that is being acted upon only by the force of gravity is said to be in a state of FREE FALL.

33
Q

Rules of Free fall:

1. Free-falling objects do not encounter air _________

A

3 rules of Free fall:

1. Free-falling objects do not encounter air RESISTANCE!

34
Q

Rules of Free fall:

2. All free-falling objects (on Earth) accelerate downwards at a rate of __ m/s2.

A

Rules of Free fall:

2. All free-falling objects (on Earth) accelerate downwards at a rate of 10 m/s2.

35
Q

Rules of Free fall:

3. Not affected by ____ and _____ of the object.

A

Rules of Free fall:

3. Not affected by MASS and SHAPE of the object.

36
Q

Newton’s 1st law:

A

Objects at rest and objects in motion remain in motion in straight line (“persist”) unless acted upon by an unbalanced force.
Rest means - ΣF=0.

37
Q

Newton’s 2nd law:

A

Force Equals mass time acceleration:

F=ma

38
Q

Newton’s 3rd law:

A

For every action there is an equal and opposite reaction.

39
Q

What is Hooke’s Law?

A

𝐹=−𝑘*𝑥
𝐹 - Elastic Force of a Spring
𝑘 - Spring Constant (Hooke’s)
x - Displacement

40
Q

a body in motion would remain in motion unless a _____ (such as friction) caused it to come to rest.

A

a body in motion would remain in motion unless a force (such as friction) caused it to come to rest.

41
Q

If a body has a net force acting on it, it is accelerated in accordance with the ______ law of newton.

A

If a body has a net force acting on it, it is accelerated in accordance with the second law of newton.

42
Q

What law deals with the stress-strain relationship?

A

Hooke’s Law

43
Q

The ______ of the material is proportional to the applied stress within the elastic limit of that material.

A

The strain of the material is proportional to the applied stress within the elastic limit of that material.

44
Q

What is the Unit of the spring constant k?

Hooke’s Law

A

[N/m]

45
Q

____ can be defined as transfer of energy

A

Workcan be defined as transfer of energy

46
Q

If one object transfers (gives) energy to a second object, then the first object does ____ on the second object.

A

If one object transfers (gives) energy to a second object, then the first object does work on the second object.

47
Q

Lifting a weight from the ground and putting it on a shelf is a good example of ____.

A

Lifting a weight from the ground and putting it on a shelf is a good example of work.
*The force is equal to the weight of the object, and the distance is equal to the height of the shelf (W= Fxd)

48
Q

What is the relationship between Force, Distance and Work?

A

W=Fxd

Force times distance equals Energy!

49
Q

______ can be defined as the capacity for doing work.

A

Energycan be defined as the capacity for doing work.

50
Q

The energy of a moving object is called ______ energy.

A

The energy of a moving object is called kinetic energy.

51
Q

For an object of mass m, moving with velocity of magnitude v, this energy can be calculated from the formula :

A

E= 1/2 mv^2.

52
Q

What are the basic two type of energies?

A

There are two types of energy in many forms:
Kinetic Energy= Energy of Motion
Potential Energy= Stored Energy

53
Q

What are examples for Solar Energy?

A

Infrared Heat, Radio Waves, Gamma Rays, Microwaves, Ultraviolet Light

54
Q

What are processes involving for Atomic/Nuclear Energy?

A

Nuclear Fission: When a neutron splits an atom’s nucleus into smaller pieces it is called .
Nuclear Fusion: When two nuclei are joined together under millions of degrees of heat.

55
Q

What is Electrical Energy ?

A

The generation or use of electric power over a period of time expressed in kilowatt-hours (kWh), megawatt-hours (NM) or gigawatt-hours (GWh).

56
Q

What is Chemical Energy ?

A

Chemical energy is a form of potential energy related to the breaking and forming of chemical bonds. It is stored in food, fuels and batteries, and is released as other forms of energy during chemical reactions.

57
Q

What is Mechanical Energy?

A

Energy of the moving parts of a machine. Also refers to movements in humans

58
Q

What is Heat Energy ?

A

A form of energy that is transferred by a difference in temperature

59
Q

What is Power?

A

Power is the work done in a unit of time. In other words, power is a measure of how quickly work can be done.

60
Q

What is the Unit of Power?

A

The unit of power is the Watt = 1 Joule/ 1 second.

61
Q

What are the units for Energy and Work?

A

Joules (J)

For both

62
Q

What is the formula for Power?

A

P = E / t

63
Q

Constant for conversion of E to m?

Energy to Mass

A

E=mc^2

64
Q

What does the mass-equivalence state?

A

In specific situations Mass can be converted to Energy of a proportion that is equivalent to the mass times the speed of light square! (and vice versa)