Question

If a car can go from 0 to 60 mi/hr in 8.0 seconds, what would be its final speed after 5.0 seconds if its starting speed were 50 mi/hr?? PLEASE HELP ME WORK THIS OUT - i will fan you and give free medals

Answer 1

Let's use Newton's Laws of Motion to determine a few things...

First, the acceleration of the car:
a=v f −v i t , where v f =26.82ms ;v i =0;t=8.0s


a=26.82−08.0 =3.35ms 2


Now, to determine the final speed when v i =22.35ms ;t=5s;a=3.35ms 2


v f =v i +at
v f =22.35+3.35⋅5=39.1ms



The same problem in English units of miles per hour:


Acceleration of the car from 0mi/h to 60mi/h in 8.0s:


a=v f −v i t , where v f =60mi/h;v i =0;t=8.0s


a=60mi/h−08.0s =7.5mi/h/s


Final speed when initial velocity is 50mi/h:


v i =50mi/h ; a=7.5mi/h/s ; t=5.0s


v f =v i +at


v f =50mi/h + (7.5mi/h/s )(5.0s )


v f =50mi/h+37.5mi/h=87.5mi/h