Forces 2 Flashcards
Examples of scalar quantitates (6)
Temperature
Mass
Speed
Energy
distance
Time
(TEMSDT)
Scalar quantities have a magnitude only (size) but not a …
E.g temperature, energy, mass, distance, time, speed
Direction
How to use arrows to represent vectors
Length of arrow= magnitude of vector
Direction of arrow= direction of vector
Force definition
A force is a push or pull that acts on an object due to the interaction with another object
A force is a push or a pull that acts on an…
Object due to the interaction with another object
In contact forces the 2 objects must be….
Physically touching
For the normal contact force to be exerted, the 2 objects must be in …contact
Direct
E.g a lamp on a table
Non contact vs contact forces
In contact forces, the 2 objects must be physically touching e.g air resistance, friction, normal contact force and tension
In non contact forces, the 2 objects aren’t physically touching e.g weight, electrostatic, magnetic
Definition for weight of object
Weight is the Force acting on the object due to gravity
Weight is the force acting on an object due to..
Gravity
(Definition of weight)
Which changes out of weight and mass
Weight- depends on location of object as weight= mass x gravitational field strength and gravitational field strength changes
Mass never changes (it’s how much matter an object has- an elephant has the same amount on matter on the earth as on the moon)
2 pieces of equipment used to determine objects weight
Newton meter
Calibrated spring balance
2 pieces of equipment used to determine weight of object are Newton meter and …spring balance
Calibrated
Centre of mass definition
Where weight of object acts at a single point
2 scenarios when resultant force is 0
Object is stationary
Object is moving at a constant speed
Name for forward force acting on moving objects
Thrust
Why does kinetic energy get transferred to thermal energy when a car brakes
Friction acts between brake and wheel
Kinetic energy of car transferred to thermal energy store of brakes
(So car slows down as it loses kinetic energy)
Important thing to remember in terms of force used when calculating work done (force x distance moved)
Only use force that’s acting in line with the distance (even if the object has forces acting on it in lots of different directions)
Inelastic deformation meaning
When forces acting on object are removed, the object doesn’t return back to its original length or shape
Moment definition
Turning effect of a force
Name for turning effect of a force
Moment
Distance used when calculating moment (moments force x distance)
Distance perpendicular to line of action from force
True or false, particles collide at right angles with the walls of the container
False
They exert a force at right angles to the wall of the container when they collide (but don’t collide at right angles)
Which out of solids, liquids and gases are fluids
Liquids and gases
The atmosphere gets…dense as altitude increases (higher up into the sky/ further away from the surface of the earth)
Less
Water has a higher pressure at the…of the container
Bottom
(Like sky- pressure increases higher up)
2 relevant forces for talking about whether object floats or sinks
Upthrust (upward force)
Weight (downward force of object)
Upthrust equal to weight = object floats
Weight greater than upthrust= object sinks
Relationship between weight and upthrust for object to float in water
They are equal
Key fact to learn!
How to determine size of upthrust force acting on object in water when object has just been lowered into water
It equals the weight of water that the object has displaced
What type of objects have a momentum
Objects that are moving
Conservation of momentum meaning
In a closed system total momentum before an event is equal to total momentum after an event
…changes in momentum can be dangerous (as they lead to a huge force being applied)
Rapid
Newton’s 3 laws of motion describe the effect of….on the…of an object
Forces
Motion
Newton’s second law of motion
Force = mass x acceleration
(Force and acceleration are directly proportional)
(Acceleration and mass are inversely proportional)
Newton’s 3rd law of motion
When 2 objects interact with each other, they exert equal and opposite forces on each other
Inelastic deformation is where when…are removed the object doesn’t return to its original shape or length
Forces acting on an object
Centre of mass of object is where…of object at a single point
Weight
Centre of mass of object is where weight of object…
Acts at a single point
