P 8 Flashcards
What is a scalar quantity ?
Scalars are quantities that only have magnitude .
What is a vector quantity ?
Vectors have both magnitude and direction
What are the 8 examples of scalar quantities ?
Distance
Speed
Mass
Energy
Volume
Density
Temprature
Power
What are 6 examples of vector quantities ?
Displacement
Velocity
Weight
Force
Acceleration
Momentum
How can we represent a vector quantity ?
We can represent it by using an arrow
When representing a vector what does the length of the arrow represent ?
The magnitude of the vector
When representing a vector what does the direction of the arrow represent ?
The direction of the vector
What is a force ?
A force is a push or a pull that acts on an object .
What are the six main forces ?
- weight
- electrostatic
- thrust
- air resistance
- compression
- tension
What are the two types of forces ?
Contact and non contact forces
What is the unit for force ?
Newtons
What does Newtons third law state ?
When two objects interact with each other , the exert equal and opposite forces on each other .
How do you calculate weight ?
mass x acceleration due to gravitational field strength
What is an resultant force ?
A single force that describes all of the forces acting on an object .
What does newtons first law of motion state ?
If forces acting on an object are balanced , the resultant force is zero .
How can a resultant force be calculated ?
By adding or subtracting all of the forces acting on an object .
What do you do when forces are working in opposite directions when working out resultant forces ?
They are subtracted from each other .
When working out resultant forces , if their are forces working in the same direction what do you do ?
add them
What is tension ?
The force experienced by a cable , rope , or string when pulled , hung rotated or supported .
What is friction ?
The force that arises when two surfaces are in contact of each other .
What is the centre of mass of an object ?
The point at which its mass can be thought of as being concentrated .
For a flat object that is symmetrical , where is its centre of mass ?
along the line of symmetry
For irregular objects , what equipment do you need to find the centre of mass ?
A stand , plumbline , small weight and card .
What is the method for an irregular object for the centre of mass ?
- Put a hole in one corner of the card and suspend the card from the rod .
- Use a plumb line to draw a vertical line on the card from the rod .
- Repeat the procedure , hanging the card from a different corner .
- Wherever the two lines cross , that is the line of symmetry .
