Starting from rest, a dragster travels a straight 1/4 mi racetrack in 6.70 s with constant acceleration. What is its velocity when it crosses the finish line?

Its velocity when it crosses the finish line is 119.40 m/s

Explanation:

We have equation of motion s = ut + 0.5 at²

Initial velocity, u = 0 m/s

Acceleration, a = ?

Time, t = 6.70 s

Displacement, s = 1/4 mi = 0.25 mi = 400 m

Substituting

s = ut + 0.5 at²

400 = 0 x 6.70 + 0.5 x a x 6.70²

a = 17.82 m/s²

Now we have equation of motion v = u + at

Initial velocity, u = 0 m/s

Final velocity, v = ?

Time, t = 6.7 s

Acceleration, a = 17.82 m/s²

Substituting

v = u + at

v = 0 + 17.82 x 6.7

v = 119.40 m/s

Its velocity when it crosses the finish line is 119.40 m/s