P2.2 Flashcards

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1
Q

What force opposes gravity?

A

The reaction force

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2
Q

What can a force do?

A

Change the shape of an object
Change an object’s motion

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3
Q

What do changes in motion include?

A

Being at rest (not moving) and acquiring a velocity
Travelling at a constant velocity and INCREASING in velocity
Travelling at a constant velocity and DECREASING in velocity
Travelling at a constant velocity and CHANGING DIRECTION

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4
Q

How can you represents forces in diagrams?

A

As arrows

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5
Q

What is the difference between the force of gravity and an electrostatic force?

A

The force of gravity is only attractive but an electrostatic force can be attractive or repulsive

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6
Q

What happens when 2 opposing forces are balanced?

A

You move at a constant (uniform) speed

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7
Q

What is a non-contact force?

A

When two object give rise to a force without touching, the forces that emerge are called non-contact forces

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8
Q

What is newtons 3rd law?

A

When two bodies interact, they exert a force upon each other that is equal in size, but opposite in direction

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9
Q

Why are tension and compression similar?

A

Compression is the force acting opposite to tension

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10
Q

What is a free body diagram?

A

A diagram that shows all the forces acting on a single body

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11
Q

What is the meaning of forces acting in the horizontal plane?

A

If two forces act left and right

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12
Q

What is the meaning of forces acting the vertical plane?

A

If two forces act up and down

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13
Q

What is resultant force?

A

The total force of forces that act in the sample plane

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14
Q

How can you find resultant force?

A

By adding or subtracting two forces acting on the same plane

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15
Q

How do you work out the resultant force of two forces that aren’t on the same plane?

A

You connect them making a triangle and use pythagorus’s theorem or trigonometry to find the hypotenuse which is the resultant force

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16
Q

What is Newton’s 2nd law?

A

The acceleration experienced by a body is directly proportional to the resultant force acting upon it and in the same direction as it.

17
Q

How do we know if the body is accelerating?

A

If the speed and/or direction of motion change

18
Q

What is the formula for resultant force when we don’t know the forces?

A

Mass (Kg) x acceleration (m/s^2)

19
Q

What is the formula for acceleration?

A

Final velocity (m/s) - initial velocity (m/s)
———————————————————
Time (seconds)

20
Q

What is the centripetal force?

A

When an object is constantly accelerating and so must be subject to a resultant force

21
Q

What does the centripetal force do?

A

It always acts towards the centre of the circle and acts only the change the direction of the velocity (not the size).

22
Q

What is terminal velocity?

A

When the forces on you are are equal and your motion no longer changes

23
Q

What is momentum and why do you need to be careful when doing calculation?

A

It is a vector so you need to take account of direction

24
Q

What is the formula for momentum?

A

Mass (Kg) x velocity (m/s)

25
Q

How do you calculate velocity of two bodies after a collision using momentum?

A

You find the total momentum before the collision
That total momentum would equal the total mass of the bodies multiplied by the momentum after. Meaning you would do:
Momentum before
—————————-
Total mass
To give the velocity of the two trolleys after

26
Q

What is the equation for work done?

A

Force (N) x Distance (M)

27
Q

What are the units for work done?

A

Joules

28
Q

What is 1 newton-metre the same as?

A

1 joule

29
Q

How do you calculate power?

A

Work done (J)
———————
Time (s)

30
Q

What are the units for power?

A

Watts

31
Q

What is work in science?

A

It is about using forces to transfer energy between stores

32
Q

What are joules equal to?

A

1 Joule = 1 newton-metre

33
Q

What is power?

A

The rate at which energy is transferred

34
Q

What is the formula for power?

A

Work done (J)
———————
Time (s)

35
Q

What are the units for power?

A

Watts