Question

What is the expression for average velocity?

Answer 1

Dear student,


If you're more comfortable with a proof written as formulas, you can start with the formula for distance traveled assuming constant acceleration, and derive this formula from there:

• s = ut + ½at². (Technically Δs and Δt, or change in position and change in time, but you'll be understood if you use s and t.)
• Average velocity v_av is defined as s/t, so let's put the formula in terms of s/t.
• v_av = s/t = u + ½at
• Acceleration x time equals the total change in velocity, or v - u. So we can replace "at" in the formula and get:
• v_av = u + ½(v- u).
• Simplify: v_av = u+ ½ v - ½ u = ½ u + ½ v= (v + u)/2.

Regards