P8 Forces in balance Flashcards

1
Q

What is displacement?

A

Distance in a given direction

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2
Q

what is a vector quantity?

A

A vector quantity has magnitude and direction

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3
Q

What is a scalar quantity?

A

A scalar quantity has only magnitude

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4
Q

what are five examples of vector quantities?

A
  • Acceleration
  • Force
  • Momentum
  • Weight
  • Velocity
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5
Q

what are six examples of scalar quantities?

A
  • Speed
  • Distance
  • Time
  • Mass
  • Energy
  • Power
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6
Q

How to represent a vector quantity

A

A vector quantity can be represented by an arrow in the direction of the vector and of length in proportion to the magnitude of the vector

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7
Q

what is Newton’s third law?

A

States that when two objects interact with each other, they exert equal and opposite forces on each other

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8
Q

What is a contact force?

A

A force that acts on objects only when the objects touch each other

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9
Q

what is Newton’s first law?

A

States that if the forces acting on object are balanced, the resultant force on the object is zero, and:
- if the object is at rest, it stays stationary
- if the object is moving, it keeps moving with the same speed and in the same direction

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10
Q

What does it mean if the resultant force on an object is zero?

A

If only two forces act on an object with zero resultant force, the forces must be equal to each other and act in opposite directions

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11
Q

What is the resultant force?

A

A single force that has the same effect as all the forces acting on an object

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12
Q

How to calculate the resultant force when an object is acted on by two unequal forces in opposite directions?

A

The resultant force is equal to the difference between the two forces, in the direction of the larger force

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13
Q

How to calculate the resultant force when an object is acted on by two forces acting along the same line?

A

The resultant force is equal to the sum of the two forces, in the same direction as the two forces

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14
Q

A free-body diagram

A

Shows the forces acting on an object without any other objects or other forces shown

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15
Q

How to calculate the moment of a force

A

moment = force x perpendicular distance
M = F x d

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16
Q

How to increase the moment of a force in general

A
  • Increase the magnitude of the force
  • Increase the distance
17
Q

How the moment of a force can be increased - spanner

A

The turning effect of a force, called the moment of the force, can be increased by:
- increasing the size of the force
- using a spanner with a long handle

18
Q

What is the moment of a force?

A

A measure of the turning effect of the force on an object

19
Q

what are levers?

A

Can be used to exert a force that is greater than the effort

20
Q

Load

A

The weight of the object

21
Q

What three parts make up a lever system?

A
  • Load
  • Effort
  • Pivot
22
Q

How can a lever be used as a force multiplier?

A
  • If the distance between the effort and pivot is greater than the distance between the pivot and load, the force applied on the load is greater than the effort force
  • This is because the moment on both the effort and load must be the same
23
Q

Examples of contact forces

A
  • Friction
  • Air resistance
  • Tension
  • Normal contact force
24
Q

Examples of non-contact forces

A
  • Gravitational force
  • Electrostatic force
  • Magnetic force
25
Q

What is a force?

A

A push or pull that acts on an object due to the interaction with another object

26
Q

What is a contact force?

A

A force that acts on objects only when the objects touch each other

27
Q

What is a non-contact force?

A

A force that acts on objects at a distance, the objects are separated

28
Q

Why is a door handle placed on the opposite side of the hinge?

A
  • For a given force, the perpendicular distance from the pivot is larger
  • This creates a larger moment to make it easier to open the door
  • Opening a door with a handle close to the pivot would be much harder, and require a lot more force
29
Q

What is the principle of moments?

A

States that if an object is unbalanced, the total clockwise moment about a pivot equals the total anticlockwise moment about the pivot

30
Q

what are the two categories that all forces can be split into?

A

contact and non-contact forces

31
Q

give three examples of contract forces

A
  • friction
  • tension
  • air resistance
32
Q

give three examples of non-contact forces

A
  • magnetic
  • gravitational
  • electrostatic