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Grade 8: Physics Term 1-2 > Forces > Flashcards

Forces Flashcards

1
Q

What is a force?

A

Push/pull/twist that cannot be seen, but can see the effect on an object.

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2
Q

What are the 4 effects of a force?

A
  1. Change the position
  2. Change the direction/speed
  3. Change the shape (deform)
  4. Cause rotation
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3
Q

What are the two types of forces? Explain each.

A
  1. Contact forces - forces that occur when 2 objects are touching
  2. Non-contact forces - forces that occur even though objects are separated by distances.
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4
Q

Name 7 contact forces.

A
  1. Air resistance
  2. Friction
  3. Tension
  4. Reaction
  5. Applied force
  6. Spring force
  7. Normal force
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5
Q

Name 3 non-contact forces.

A
  1. Magnetic force
  2. Electrostatic force
  3. Gravitational force
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6
Q

What is the symbol for force?

A

F (NOT “f”)

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7
Q

What is the SI unit for force?

A

Newtons/N (NOT “n”)

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8
Q

Name 2 things to measure the magnitude of relatively small forces.

A

Spring balance

Newton meter

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9
Q

What is magnitude?

A

Size.

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10
Q

What are Newton’s 3 laws of motion?

A

LAW 1: An object will remain still/keep travelling at a constant velocity when all the forces acting on it are balanced (equal/cancel out).
LAW 2: An object will accelerate in the direction of the resultant force when all the forces acting on the object are unbalanced.
LAW 3: When 2 objects interact, the forces they exert on each other are equal in size and opposite in direction.

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11
Q

What is a vector?

A. Despicable Me Movie character
B. Quantity that has a magnitude
C. Quantity that has a magnitude and direction
D. Quantity that has a direction

A

C.

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12
Q

What is a scalar?

A. A word
B. Quantity that has a magnitude
C. Quantity that has a magnitude and direction
D. Quantity that has a direction

A

B.

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13
Q

What are balanced forces?

A

Forces that are the same size, but in opposite directions.

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14
Q

What are unbalanced forces?

A

Forces that are not equal and opposite, which results in a change in speed/direction.

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15
Q

What is equilibrium?

A

When the resultant force equals zero.

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16
Q

What is a force diagram?

A

Displays all the forces acting on an object as arrows, pointing in the direction of the effect. This can be simplified by using the object’s centre of gravity.

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17
Q

What is friction?

A

Resistance to motion.

18
Q

What are the 3 effects of friction?

A

Slows moving objects down
Causes objects to heat up
Wears surfaces out

19
Q

How is friction created?

A

Friction is created when two touching objects/surfaces move past each other.

20
Q

How can friction be reduced?

A

Lubrication and streamlining.

21
Q

What is air resistance?

A

Friction that occurs in the air.

22
Q

What is water resistance?

A

Friction that occurs in the water.

23
Q

Air + water resistance = _______.

A

Drag.

24
Q

What is thrust?

A

Force that pushes an object forward.

25
Q

What is upthrust?

A

Force that pushes an object upwards in a liquid/gas = buoyancy.

26
Q

What is tension?

A

Force exerted by a rope, string, chain, cable, spring etc.

27
Q

What is extension?

A

The amount that an object gets longer when you stretch it.

28
Q

What is fluid?

A

A substance that continually flows under an applied sheer stress, or external force.

29
Q

What is mass?

A

Amount of matter in an object that remains the same throughout the universe.

30
Q

Mass is a scalar/vector.

A

Scalar.

31
Q

What is the symbol for mass?

A

m (NOT “M”)

32
Q

What is the SI unit for mass?

A

kilogram or kg (NOT “KG” or “Kg” or “kG”)

33
Q

What equipment is used to measure mass?

A

Balance.

34
Q

What is weight?

A

Gravitational force that the object’s mass experience in a gravitational field.

35
Q

Weight is a scalar/vector.

A

Vector.

36
Q

What is the symbol for weight?

A

W (NOT “w”)

37
Q

What is the direction for weight?

A

Towards the center of the Earth (on Earth).

38
Q

What equipment is used to measure mass?

A

Spring balance.

39
Q

Is the weight of an object unique to the gravitational field?

A

Yes.

40
Q

What is the formula for weight?

A

W = m x g

W = weight
m = mass
g = gravity
41
Q

What is the centre of gravity?

A

Point through which all the weight of an object seems to act.

Grade 8: Physics Term 1-2 (8 decks)

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