Final answer:
When avoiding a collision, you should make changes in course and speed perpendicular to the direction you are currently traveling.
Step-by-step explanation:
When you act to avoid a collision, you should make your changes in course and speed at right angles to the course you are steering.
For example, if you are driving a car and need to avoid hitting an obstacle, you should steer to the left or right, perpendicular to the direction you are currently traveling.