# P2: Forces and Motion

HideShow resource information
• Created by: ja7sa096
• Created on: 20-04-16 21:35
What is a force?
Any influence that causes an object to undergo a specific change
1 of 37
What are the units ofr force?
Newtons (N)
2 of 37
Whenever to objects push or pull on each other...
They exert equal and opposite forces on one another
3 of 37
What is resultant force?
The sum of the individual forces.
4 of 37
Why does force have to have a direction?
Because it is a vector
5 of 37
What is zero resulatant force?
When the resultant force on an object is zero because: it remains stationary or continues to move at the same speed in the same direction
6 of 37
What is non-zero resulatnt force?
When the resultant force on an object is not zero
7 of 37
If an object is acted on by two unequal forces in opposite directions, the resultant force is...
Equal to the difference between the two forces, in the direction of the larger force
8 of 37
What is a balanced force?
Where the forces are of equal size in opposite directions, resultant force is 0, objects are stationary/constant speed
9 of 37
What is an unbalanced force?
Where the forces are of unequal size in opposite directions, resultant force>0, acceleration
10 of 37
What types of forces are there?
Push, pull, upthrust, weight, friction, air/water resistance (drag), tension, reaction, lift and force from the engine (thrust)
11 of 37
Resultant force is proportional to...
Acceleration
12 of 37
Mass is inversely proportional to...
Acceleration
13 of 37
How do we calculate force?
Mass (kg) * Acceleration (m/s squared)
14 of 37
How do we calculate mass?
Force/acceleration
15 of 37
How do we calculate acceleration?
Force/mass
16 of 37
What is mass?
The amount of matter (particles) in an object
17 of 37
What is mass measured in?
Kilograms
18 of 37
What is the gravitational field strength on Earth?
9.8 (10)
19 of 37
How do we calculate weight (N)?
Mass (kg) * gravitational field strength (m/s squared)
20 of 37
What is the gravitational field strength o the moon?
1.6
21 of 37
In a vaccuum, everything will fall at the ............, irrospective of the mass
Same rate
22 of 37
Describe the process of a parachutist falling through the sky.
Weight makes her accelerate, as she accelerates so will air resistance, weight and air resistance balance out (constant speed/terminal velocity), opens parachute and increases air resistance, decelerates, air resistance and weight balance out again
23 of 37
Force is proportional to...
Extension
24 of 37
What is Hooke's Law?
The force applied to a material is directly proportional to the extension as long as it remains within the limit of proportionality
25 of 37
What is the limit of proportionality?
The point at which the material will not return back to its original state
26 of 37
How do we calculate Hooke's Law?
Force (N) = Spring constant (N/m) * Extension (m)
27 of 37
What axis does extension go on?
X axis
28 of 37
What axis does force go on?
Y axis
29 of 37
What is the gradient of a force extension graph?
Spring constant
30 of 37
What does friction do?
Slow things down
31 of 37
Reaction forces are always...
Equal and opposite
32 of 37
Drag increases as the .... increases
Speed
33 of 37
What is terminal velocity?
When the force is equal to the resistance, resultant force is 0, moving at constant speed
34 of 37
What do objects have to fall through to reach terminal velocity?
Fluids
35 of 37
What do frictional forces increase with?
Speed
36 of 37
Explain why the car reaches top speed, even though the thrust force remains constant.
As speed increases so does drag, thrust=drag and they balance out, resultant force=0
37 of 37

## Other cards in this set

### Card 2

#### Front

What are the units ofr force?

Newtons (N)

### Card 3

#### Front

Whenever to objects push or pull on each other...

### Card 4

#### Front

What is resultant force?

### Card 5

#### Front

Why does force have to have a direction?