Flashcards in 1. General Physics Deck (54)
How to calculate speed?
Total distance / time taken
Interpret speed time graph
Area underneath = distance travelled
Flat line = constant speed
Straight line going up/down: constant acceleration or deceleration
Acceleration not constant -> curve
Interpret distance- time graph
The slope= speed
The steeper the slope the grater the speed
Flat line= stop
Curve up= slowing down and vice versa
What is acceleration
The change of velocity per second
How to calculate acceleration
Change in velocity / time taken for the change
Acceleration of free fall for a body near to the earth?
What is velocity?
Speed in given direction
What happen to the motion of a falling body
Object are slow down by air resistance
Air resistance gets bigger as accelerate
Once air resistance = force of gravity, the object has reached terminal velocity
Object stay at a constant velocity
What is terminal velocity
When a free falling body air resistance force and gravity force is equal and the object will stay at a constant velocity.
What is mass?
A measure of the amount of matters a body contains
What is inertia
An object's resistance to a change in its motion
The greater the mass, the more inertia it has
How to calculate weight?
1kg = 10N
What is density
How tightly packed matter is and the amount of mass in a given space
How to calculate density?
What is the density of water and when does an object sink in water?
Density of water= 1g/cm3
Density of object > density of water => sink
How to measure volume of a irregular object?
Put the object into measuring cylinder with water. When you add the object, it displaces the waters, making the water level rises
The rise= volume of object
What is the effect of force?
Change in size, shape, speed or direction
What is elastic
When an object regains its original shape when the force that deform it are removed -> it is elastic
What is elastics limit?
The limit to which an object can be stretched without being permanently extended
What is hooke's law?
K is spring constant, extension is directly proportional to the weight
What is the name when the force no longer directly proportional to the extension?
Limit of proportionality
What is resultant force?
A single force that has the same effect as all the forces acting on the object
What happen when resultant force =0
The object remain at rest if it was already at rest
Continue to move at the same speed and in the same direction if it was already moving
How to calculate force?
Mass x acceleration
Describe circular motion
An object moving around a circular path is acted by a resultant force which is directed towards the cent of the circle
The resultant force is called the centripetal force
What is moment?
What is moment of the force
The turning effect of the force
Measured in Newton
Can be either clockwise or anticlockwise
How to calculate moment?
Force x perpendicular distance to pivot
F x d
Describe an object in equilibrium
No resultant force on it
No resultant turning force on it