Chapter 2 - Kinematics Flashcards
What is a scalar quantity?
A physical quantity that has only magnitude
Examples of scalar quantities
distance speed mass volume temperature energy density time
What is a vector quantity?
A physical quantity that has both magnitude and direction
Examples of vector quantities
displacement velocity acceleration weight force
Define “speed”
The rate of change of distance of an object at a specific instant
Define “velocity”
The rate of change of displacement of an object at a specific instant
Calculation of average speed
total distance ÷ total time
Calculation of average velocity
total displacement ÷ total time
Define “acceleration”
The rate of change of velocity at a specific instant
Calculation of average acceleration
change of velocity ÷ total time taken
a = (v-u)/t
50 dots per second on a ticker tape timer means frequency (f) = ________
50 Hz
The time interval between two dots (1 dot interval) = ________
1/f
Distance-time graph: gradient represents ________
speed
Displacement-time graph: gradient represents ________
velocity
Speed-time graph: gradient represents ________ and area under graph represents ________
acceleration (if motion in a straight line in one direction) or only magnitude of acceleration (otherwise)
distance (only positive)
Velocity-time graph: gradient represents ________ and area under graph represents ________
acceleration
displacement (can be positive or negative)
What is a free-falling object?
An object that falls under the sole influence of gravity (without air resistance)
All objects in free fall near the surface of Earth experience an acceleration of ________
10ms^-2
When there is no air resistance, all objects, regardless of their mass or size, will fall at the same rate
True or False?
True
When there is no air resistance, any two objects, when released from the same height, will reach the ground at ________
the same time
If an object is dropped from a height, then its initial velocity (u) is ________
0ms^-2
If an object is projected upwards in an perfectly vertical direction, its velocity is ________ at the highest point of its motion
0ms^-2
If an object is projected upwards in an perfectly vertical direction, the velocity at which it is projected is ________ in magnitude and ________ in direction to the velocity that it has when it returns to the same height
equal
opposite
Four equations of motion
- v = u + at
- s = ut + 1/2at^2
- v^2 = u^2 + 2as
- s = (u + v)/2 t
The four equations of motion are only applicable for motion with ________
uniform acceleration
Air resistance will ________ when the velocity of a falling object increases
increase
When will an object fall with terminal velocity?
At the point when air resistance is equal to the weight of the object (there is no acceleration)
Objects with high density have ________ terminal velocity
high
Objects with low density have ________ terminal velocity
low
In a vacuum, there is no air resistance, so the ________ is constant
acceleration due to gravity
