two motorcycles are traveling due east with different velocities. however, 2.10 seconds later, they have the same velocity. during this 2.10-second interval, motorcycle a has an average acceleration of 1.90 m/s2 due east, while motorcycle b has an average acceleration of 17.8 m/s2 due east. (a) by how much did the speeds differ at the beginning of the 2.10-second interval, and (b) which motorcycle was moving faster? (a)