Velocity and acceleration Flashcards
What is rate of movement?
One of the simplest things we can measure is how fast an object is moving. You can calculate an object’s SPEED if you know the amount of time taken to move a certain distance.
speed(m s-1) = distance(m) / time(s)
v = d/t
What is velocity?
The calculation for speed will only tell you how fast an object is moving. Also, it’s vitally important to know in what direction this movement is taking the object. When you include the direction in the information about the rate of movement of an object, this then known as the velocity.
What is the formula for VELOCITY?
The velocity is the rate of change of DISPLACEMENT, where the distance in a particular direction is called the ‘displacement’.
velocity (m s-1) = displacement (m) / time (s)
v = s/t OR v = Δs / Δt
What is the difference between a VECTOR and SCALAR quantity?
A quantity for which direction must be stated is known as VECTOR. If direction is not important, the measurement is referred to as a SCALAR quantity. Therefore, velocity is a vector and speed is a scalar, distance is a scalar and displacement is a vector.
What is a average speed?
Average speed is calculated by dividing the total distance for a journey by the total time for the journey.
What is instantaneous speed?
Instantaneous speed can be an important quantity - is is the speed on an object at given moment in time - which can be found from the gradient of the tangent to a distance-time graph.
What is acceleration?
This is defined as the rate of change of velocity. Therefore, it must include the direction in which the speed is changing, and so acceleration is a vector quantity.
What is the formula for acceleration?
Acceleration (m s-2) = change in velocity(m s-1) / time taken to change the velocity(s)
a = v - u / t
OR a = Δv / Δt
Where u is initial velocity and v is the final velocity.
Why is the vector nature of acceleration is very important?
The reason it is important is that consequence of this is that if an object changes direction, it is accelerating, whilst remaining at a constant speed. Also, deceleration represents a negative change in velocity, and so could be quoted as a negative acceleration.
Speed
Speed is the rate of change of distance.
speed( m s-1) = distance( m) / time (s)
v = d / t
Velocity
Velocity is the rate of change of displacement.
Displacement
Displacement is the vector measurement of distance in a certain direction.
Vector
A vector quantity must have both magnitude and direction.
Scalar
A scalar quantity has only magnitude.
