Forces and energy (Year 8) Flashcards

1
Q

what type of surface has a large amount of friction

A

rough surface

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2
Q

what type of surface has a small amount of friction

A

smooth surfaces

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3
Q

what is the unit used to measure force

A

newton

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4
Q

A box is pulled to the right with 6 N and to the left with 6 N. The resultant force is

A

zero newtons

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5
Q

The force of friction is ALWAYS in this direction

A

opposite to the direction of motion

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6
Q

forces are…

A

Pushes or Pulls

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7
Q

what is a resultant force

A

the overall value of the forces acting on an object after considering the direction of the forces

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8
Q

what is an unbalanced force

A

when the forces are NOT EQUAL to each other in a particular direction. Gives a resultant force

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9
Q

what is a balanced force

A

the force that does NOT change an object’s motion because the forces are equal and opposite so therefore cancel each other out

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10
Q

mass

A

the measure of the amount of matter in an object

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11
Q

is gravity a non contact force

A

yes

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12
Q

what is terminal velocity

A

the fastest speed reached by a skydiver when the weight and drag forces become equal

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13
Q

define upthrust force

A

force that allows an object to float in a fluid.

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14
Q

Acceleration is equal to

A

force divides by a mass

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15
Q

define thrust

A

this is the push of an engine and acts in the forward direction

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16
Q

what is tension

A

the force inside a stretched rope , string or reaction. it acts in a direction to return the object to its original shape

17
Q

forces can cause 3 things to happen, What are they ?

A
  1. can cause a change in state
  2. can cause a change in direction
  3. can cause a change in speed
18
Q

what device is used to measure a force

A

newton meter

19
Q

name the 8 forces that we have learnt

A

friction
drag or air resistance
tension
weight
thrust
lift
normal contact
upthrust

20
Q

simplify
weight= mass x gravitational field strength

21
Q

what is measured in meters per second squared. It tells you how quickly the object is changing its speed, while it is …

A

acceleration

22
Q

what is deceleration

A

If it is slowing down, it is losing speed every second. This is called a deceleration (be careful with the spelling).

23
Q

mass is equal to …

A

forces divided by acceleration

24
Q

force is equal to …

A

mass multiplied by acceleration

25
what is the value of the gravitational field strength on the earth
10 N/kg
26
define weight
the measure of the amount of gravity pulling down on an object. It depends on the gravitation field strength
27
What MUST you include when representing forces on a diagram
arrow, label, value, unit
28
The forces of weight ALWAYS acts in what direction
Straight down
29
what is the unit for mas
kg
30
what are the units for gravitational field strength
N/kg