Constant acceleration: A dragster starts from rest and travels 400 m in 6.70 s with constant acceleration. What is its velocity when it crosses the finish line?
A) 410 km/h
B) 430 km/h
C) 450 km/h
D) 420 km/h

Question

Quizplus · Accepted Answer

To find the final velocity, use the formula $ v = u + at $. Since the dragster starts from rest, $ u = 0 $. First, find the acceleration using $ s = ut + \frac{1}{2}at^2 $, where $ s = 400 $ m and $ t = 6.70 $ s. Solving for $ a $, we get $ a = \frac{2s}{t^2} = \frac{2 \times 400}{6.70^2} \approx 17.84 $ m/s². Then, $ v = 0 + 17.84 \times 6.70 \approx 119.5 $ m/s. Converting to km/h, $ v \approx 119.5 \times 3.6 \approx 430 $ km/h.

Constant Acceleration: a Dragster Starts from Rest and Travels 400