Question

A car starts from rest and accelerates at 0.80m/s² for 10s. It then continues at constant velocity. Twenty seconds (20s) after it began to move, the car has a

(A) velocity of 8.0 m/s and has traveled 40 m

(B) velocity of 8.0 m/s and has traveled 80 m. 

(C) velocity of 8.0 m/s and has traveled 120 m. 

(D) velocity of 16 m/s and has traveled 160 m. 

(E) velocity of 16 m/s and has traveled 320 m.

 

Answer 1

Correct option (C) velocity of 8.0 m/s and has traveled 120m

For the first part v = at = 8.0m/s and d = ½ at² = 40m. In the second part of the trip, the speed C remains at 8 m/s, and travels an additional d = vt = 80m.