Video Transcript
Two motorcycles A and B are moving in the same direction. If the velocity of A is 30 kilometers per hour and the velocity of B is 15 kilometers per hour, find the relative velocity of A with respect to B.
In this example, we want to find the relative velocity of motorcycle A and that of motorcycle B which are traveling in the same direction. To calculate this, we recall that for two bodies A and B moving with velocities ๐ A and ๐ B, respectively, the relative velocity of A with respect to B is ๐ AB and that ๐ A minus ๐ B.
If we let the velocity of motorcycle A be ๐ A, which is 30 kilometers per hour, and the velocity of motorcycle B be ๐ B, and thatโs 15 kilometers per hour โ noting that since the motorcycles move in the same direction, theyโll have the same sign โ then the relative velocity of motorcycle A with respect to B is ๐ A minus ๐ B, which is 30 minus 15. And thatโs 15. Hence, the relative velocity of motorcycle A with B is 15 kilometers per hour.