Question

In a quarter-mile drag race, two cars start simultaneously from rest, and each accelerates at a constant rate until it either reaches its maximum speed or crosses the finish line. Car A has an acceleration of 11.6 m/s2 and a maximum speed of 108 m/s. Car B has an acceleration of 11.7 m/s2 and a maximum speed of 91.0 m/s. Which car wins the race, and by how many seconds?

Answer 1

The distance of the cars travelled before complete the race is, 1 mile _1609 m 402.25 nm 4 4 Use the kinematic equation ofmotion v = vo + at , and solve for the time taken for car A to complete the race. 108 m/s-0+(11.6 m/s2 )t 108 m/s 11.6 m/s -9.31 s Use the kinematic equation of motion v -vo + at, and solve for the time taken for car B to complete the race. 91.0 m/s 0+(11.7m/s2 )t 91.0 m/s 311.7 m/s - 7.78 s The car B wins the race by the amount of time calculated below: 9.31 s-7.78 s - 1.53 s