The Equation-free P3 (2) Flashcards
What is a force?
A pull or push acting on an object
What are the 6 types of forces?
- Gravity/Weight
- acting straight downwards - Reaction force
- acting straight upwards - Thrust/Pull/Push
- speeding an object up - Drag/Air resistance/Friction
- slowing object down - Lift
- like an aeroplane wing - Tension
- like in a rope or cable
What can an object be in balance?
When it’s gravity (weight) is the same as it’s reaction force.
[Down arrow (gravity) must be the same as the upward arrow (reaction force)]
What if an object only had a gravity force and no reaction force?
The object would accelerate downwards (There is only gravitational force)
How does an object prevent moving sideways?
When it is balanced
Horizontal forces [the arrows] must be equal to each other
How does a car keep a steady horizontal speed? (No acceleration or deceleration)
When ALL the arrows are the same. (Balanced)
Therefore if a car is going >right>, the:
Thrust - ➡️
Drag - ⬅️
Weight - ⬇️
Reaction force -⬆️
Should ALL be the same (same arrow length and width)
How does a skydiver maintain a steady vertical speed? (No acceleration towards ground or deceleration)
The skydiver’s drag force and weight force should be the exact same!
The-
Drag - ⬆️
Weight - ⬇️
Should be the same (same arrows) (balanced)
What would happen to forces (the arrows) when a car accelerates?
The thrust becomes bigger/longer than the drag.
If a car is going»_space;right», the:
Drag - ⬅️
Thrust - ➡️➡️➡️
(Not balanced) - for deceleration, the drag will be greater than the thrust.
What is a resultant force?
An unbalanced force
One arrow is bigger than the other
What would happen to the forces (arrows) if a skydiver was to accelerate towards the ground?
The drag force will be smaller than the weight.
The-
Weight - ⬇️⬇️⬇️
Drag - ⬆️
(A resultant force would occur) (also known as an unbalanced force)
What does friction do?
Slow things down
What causes an object to not move? Include friction in your answer.
When the frictional force is balanced with another force trying to move the object.
At some point the other force (trying to move the object) will be greater than the friction force and make the object MOVE.
Give me 3 types of friction.
- Static friction
- friction between solid surfaces which are gripping. (2 wood blocks) - Sliding friction
- friction between solid surfaces that are smoothly sliding (2 plastic blocks) - Resistance or “Drag” from fluids
- liquids and gases
- air inside your car will SLOW YOU DOWN
- air inside parachute will SLOW YOU DOWN
- walking on water will SLOW YOU DOWN
- the larger the object, the greater the drag.
REMEMBER: friction in fluids- the friction will increase as the speed increases (when you want to run in water you find it hard to overcome the liquid, but when walking it seems easier, as you slowed down, the water slowed down.)
What is terminal speed?
When an object has reached its maximum speed
How does terminal speed happen in an object?
When an object is first set off, the acceleration (thrust) is greater that the resistance (drag).
And remember that as speed increases, the drag also Increases.
The object’s drag force will eventually reduce the acceleration force, until both of their resistance and accelerating force is equal. (Balanced with same arrows)
When they are both balanced, the acceleration can no longer increase which means that the object has reached its TERMINAL SPEED.
