physics question

Question

The initial velocity of a military jet is 210 m/s eastward. The pilot ignites the afterburners, and the jet accelerates eastward at a constant rate for 1.70 s. The final velocity of the jet is 300 m/s eastward. What was the jet's displacement during the time it was accelerating?

Answer 1

For the equations of motion for constant acceleration, you need 3 variables and you can find the other two. The variables are v_i, v_f, a, t, and d (displacement, not distance or x_f-x_i) and i and f are initial and final.

In this case: v_i = 210 m/s (picking East as +), v_f = 300 m/s, and t = 1.7 seconds.

You want the equation that includes these 3 and the variable you want, d:

d = t(v_f+v_i)/2 you don't even have to rearrange the variables (My process is to knock out any 0s and then rearrange algebraically before plugging in values with units attached as a check of your algebra)