Linear Motions Flashcards
Understand the difference between velocity, speed, acceleration, instantaneous velocity/speed, free falling and speedometers
What is speed?
it is the measure of how fast something moves;
speed is defined as the distance covered per unit of time
What is speed measured by?
measured by a unit of distance divided by a unit of time
speed = distance/time
What is instantaneous speed?
it is the speed at any instant
What is instantaneous speed measured by?
a speedometer
What is average speed?
it is the whole distance covered divided by the total time of travel
What doesn’t average speed indicate?
it does not indicate the different speeds and variations that may have taken place during shorter time intervals
What is the equation for calculating average speed?
average speed= total distance covered/ time interval
What is velocity?
the speed of an object and specification of its distance of motion
-speed and direction of motion
What does constant velocity mean?
constant speed, no change in direction
Is a car moving round a circular motion, in constant velocity?
No, although it may be moving in a constant speed, it is changing direction
What does it mean by constant speed and constant velocity? are they the same?
When something moves at constant velocity or constant speed, then equal distances are covered in equal intervals of time
What does acceleration mean?
the rate at which velocity changes with time; the change in velocity may be in magnitude or direction or both
What is the equation for acceleration?
change in velocity/ interval of time
What is acceleration measured in?
the time unit is entered twice: one for the unit of velocity and again for the interval of time in which the velocity is changing
eg. 10 km/h.s
Do we accelerate everytime we move in a curved path?
yes , even if we are moving in a constant speed, because our direction is changing, velocity is changing
What exceptions can we make with speed, velocity and acceleration when we are moving in a straight line?
When straight line motion is being considered, it is common to use speed and velocity interchangeably.
When direction is not changing, acceleration may be expressed as the rate at which speed changes:
acceleration = change in speed/ interval of time
How do you calculate instantaneous velocity?
velocity acquired = acceleration X time
What does free fall mean?
Motion under the influence of gravity only
Normally, how much does a free falling object accelerate by, per second?
9.8 m/s^2
can be rounded off to 10 m/s^2
What is acceleration annotated as in free fall?
g
express the equation of velocity acquired (instantaneous velocity) in free fall , from rest?
v = gt
what happens to the instantaneous speeds of an object when it is in equal elevation in the path?
the instantaneous speed is the same however the velocities will be opposite; since one has gone up (eg. a ball) while the other is down
express the equation for distance fallen in free fall from rest?
d = 1/2gt^2
An object falling from free falling: how to calculate distance, from the initial speed and the speed at the first time interval?
first calculate the average speed thus 10-0/2
(/2 because there are two time intervals)
thus average speed is 5 m/s.
thus there is a 5 meter distance covered per second
