Physical quantities and measurement techniques + Motion + Density Flashcards
(23 cards)
What is a scalar quantity
Magnitude only (size)
What is a vector quantity
Has magnitude (size) and direction
Scalar quantities (6)
- Distance
-Speed - time
- mass
- energy
- temperature
Vector quantities
- Force
- weight
- velocity
- acceleration
- gravitational field strength
What is speed & how do you find it
Speed is the distance traveled per unit of time
You find it by doing distance/time
What is velocity & how do you find it
Velocity is speed in a given direction
You find velocity by doing distance in a given direction/time taken
How do you find average speed
Average speed= total distance traveled / total time taken
What is acceleration & how do you find it
Acceleration is change in velocity per unit of time
You find it by doing acceleration = change of velocity/ time
How do you know when an object is accelerating or decelerating
It an object is increasing in speed it is accelerating, if an object is decreasing in speed it is decelerating
In a distance vs time graph what will the gradient be like when
A) the object is at rest (stationary)
B) moving with constant speed
C)accelerating
A) when the object is stationary the gradient is 0 - it is a straight line
B) there is a constant increase
C) the line is curving upwards
In a speed vs time graph what does the gradient look like when
A) the object is at rest (stationary)
B) moving with constant speed
C) accelerating
A) line is on zero of the speed axis
B) horizontal line anywhere
C) a line going up diagonally
What is the area under a speed vs time graph
The area is distance
What is the approximate free fall acceleration for an object near to the surface of earth
9.8 m/s2, but you can just say 10 m/s2
What does the mass of an object determine
How much matter is in it
Standard unit of mass is kg
What is weight
A gravitational force on an object that has mass
What is gravitational field strength
Force per unit of mass
Acceleration due to gravity equation
G= weight/mass
Weight is in newtons (N)
Mass is in kg
Gravity = m/s^2
What is gravitational field strength equivalent to
Acceleration of free fall
What is weight in terms of gravity
The effect of gravitational field on a mass
Density definition
Mass per unit time
Density equation
p=m/v
M is mass in kg or g
V is volume in cm^3 or m^3
Density is kg/m^3 (depends on variables)
Density of water
- 1g/cm^3
- 1000kg/m^3
How can you tell if an object will float or sink in terms of density
- less dense than water = float
- more dense than water = sink
