Unit 1 Flashcards
6 scalar quantities:
- distance
- speed
- time
- mass
- energy
- temperature
7 vector quantities:
- force
- weight
- velocity
- acceleration
- momentum
- electric field strength
- gravitational field strength
What is speed?
Distance travelled per unit time
What is velocity?
Speed in a given direction
What is the acceleration of free fall?
9.8 m/s
What is deceleration?
Negative acceleration
What is mass?
The measure of the quantity of matter in an object at rest relative to the observer
What is weight?
A gravitational force on an object that has mass
What is gravitational field strength?
Force per unit mass
What is density?
Mass per unit volume
What may forces do?
Produce changes in the size and shape of an object
What is the spring constant?
Force per unit extension
What is the resultant force?
A force that may change the velocity of an object by changing its direction of motion or its speed
Describe the motion in a circular path due to a force perpendicular to the motion:
- speed increases if force increases (mass and radius stay constant)
- radius decreases if force increases (mass and speed constant)
- increased mass requires increased force to keep speed and radius constant
What is solid friction?
The force between two surfaces that may impede motion and produce heating
Define moment of a force:
moment = force x perpendicular distance from the pivot
When is an object in equilibrium?
When there is no resultant force and no resultant moment
What is moment of a force?
A measure of its turning effect
What is the SI unit for mass?
Kilogram
What is the SI unit for length?
metres
What is the SI unit for time?
seconds
What is the SI unit for area?
metre squared
What is the SI unit for volume?
metre cubed
What is a physical quantity?
- something that can be measured
- represented by an alphabetical letter
- contains numerical value and a unit
