What is the average speed of an object that is moving at #9 m/s# at #t=0# and accelerates at a rate of #a(t) =5-2t# on #t in [0,5]#?

1 Answer
Nov 8, 2016

Average speed is the mean of initial velocity and final velocity.

to solve this question we need to take out final velocity (#v#) and initial velocity(#u#) is already proided.

so lets proceed.

#a(t)=5-2t#
therefore accereleration at 5 seconds is -5#m/s^2#.This is derieved by puting t=5 in the above equation/function.

#a=v/t-u/t#

by putting values this we get #v=-12m/s#

so #u=9m/s# and #v=-12m/s#

#V_av= (u+v)/2#
=#-1.5m/s# .

I haven't showed the actual mathematics calculation as i hope you can easily make it,she see the procedure.