Materials - Equations of Motion

Question 1

Equations of Motion - Notes
(what do the equations of motion relate to?)
(what are the four equations which make up the equations of motion?)
(what do the different letters which make up SUVAT stand for?)

Answer 1

• Equations of motion relate the displacement of an object to its velocity, acceleration and time
• for constant acceleration, you can use a group of four equations known as SUVATs, These are:
v = u + at v = final velocity
S = ut + 1/2at^2 u = initial velocity
s = 1/2(u + v)t a = acceleration
v^2 = u^2 + 2as t = time
s = displacement

Question 2

Velocity versus Acceleration.
(what is acceleration equal to?)
(How do you work out the velocity of an object between two points?)

Answer 2

• For an object moving with a constant acceleration in one dimension, the acceleration is equal to the change in velocity over the change in time
• If you are measuring the acceleration between two points, however, you would want to do the final velocity minus the initial velocity divided by time.

Question 3

Displacement versus Acceleration.
(How can you find displacement in a velocity-time graph?)
(what group of equations can also be used to find the displacement?)

Answer 3

• The change in displacement of an object can be calculated by finding the area under a velocity-time graph.
• It can also be calculated using the SUVAT equations mentioned earlier.

Question 4

Re-arranging equations of motion

Can the equations of motion be re-arranged? If so what can they find

Answer 4

• The equations of motion can all be re-arranged to equal different things, just like v = u + at, t can be found by using t = (v - u)/a.

Question 5

Displacement versus Velocity.

How can the average velocity be found without SUVAT equations

Answer 5

• The average velocity of an object can be found by using v = change in displacement divided by change in time.

Question 6

Acceleration, velocity and displacement

How are the equations for acceleration, velocity and displacement linked? think maths

Answer 6

• the equations of acceleration, velocity, and displacement also have a second method of being obtained.
• The equations of velocity, acceleration, and displacement share a link through differentiation and integration, if you have an equation for acceleration, and you cannot rearrange it to get the equations for the other two, you can integrate it once to get the equation of velocity, and twice to get the equation for displacement.

Question 7

Non-uniform acceleration

How do you find the acceleration if it is non-linear?

Answer 7

• During periods the acceleration of an object can have a non-linear acceleration, this means that the SUVAT equations can no longer be used to find acceleration.
• To combat this you can instead read off the gradient of a velocity-time graph to obtain the acceleration of the object.