How do you devrive equations in kinematics

[DARTZ]

Okay, I really need to know exactly how to derive these formulas

(delta)x = (average)v*t

(average)v = v(subscript)f + v(subscript)i/2

a = v(subscript) - v(subscript)i/t


My physics teacher says you can use these 3 formulas to answer anyone dimension kinematics problem if the acceleration is constant. Now how do I derive these to get the formula. Please help I am very desperate and I need to know soon.

 

[rock.freak667]

Well distance=speed*time and acceleration is defined as the rate of change of velocity per unit time or (change in velocity)/time

 

[Andrew Mason]

Okay, I really need to know exactly how to derive these formulas

(delta)x = (average)v*t

(average)v = v(subscript)f + v(subscript)i/2

a = v(subscript) - v(subscript)i/tMy physics teacher says you can use these 3 formulas to answer anyone dimension kinematics problem if the acceleration is constant. Now how do I derive these to get the formula. Please help I am very desperate and I need to know soon.

These formulae are only valid if you have constant acceleration. You can derive these without calculus (well, you are using calculus but it is simple geometry) by plotting a speed vs. time diagram of an object moving with constant acceleration.

What does the area under the graph represent? (hint: area = height x width; height = v and width = $\Delta t$). How does the area relate to the maximum and minimum speeds? (think area of a triangle).

AM