Mechanics and Materials (2): On the move Flashcards
What is the equation for an object moving in a circle at a constant speed?
v = 2(pi)R/T
What are the two types of speeds you can calculate when an object has a changing speed?
Instantaneous velocity
Average velocity
What is the equation for instantaneous velocity?
v = s/t at that point
What is the equation for average velocity?
v = (delta)s/(delta)t
where:
delta s - total distance
delta t - total time
What does the distance-time graph look like for an object travelling at a constant speed?
A straight line graph through the origin
How do you find the speed of an object (moving at constant speed) on a displacement/distance-time graph?
Find the gradient of the straight line
How do you find the instantaneous speed of an object (moving at a changing speed) on a displacement/distance-time graph?
Draw a tangent at the point that you want to know the speed for and calculate the gradient of that line
What is the definition of constant velocity?
When an object moves with the same speed without changing its direction of motion
Does an object moving in a circular path have a constant velocity?
NO, as its direction is constantly changing
Can displacement have both a +ve and -ve sign?
Yes
What is the definition of acceleration?
The change in velocity per unit time
Is acceleration a scalar or vector quantity?
Vector (they can have a negative or positive value for deceleration or acceleration)
What is the definition of uniform acceleration?
When the rate of change of velocity of an object is constant
What is the equation for uniform acceleration?
a = v-u/t
What type of graphs display acceleration as the gradient?
Velocity-time graphs
What is the definition of non-uniform acceleration?
When the rate of change of velocity of an object is not constant
How do you find the acceleration at a point on a velocity-time graph if the acceleration is not constant?
Draw a tangent at that point and find the gradient of it
In what scenario can you use suvat equations?
When the acceleration is constant
How do you find the displacement from a velocity-time graph?
displacement = area under the graph