Motion: Acceleration and Velocity Vectors

Once students have mastered simple acceleration and velocity vectors (where they move in the same direction), challenge them with situations where the vectors are not in the same direction. Students often find this concept challenging, but it doesn't have to be. In this activity, students will create vector diagrams illustrating the acceleration and velocity in different situations. The suggested scenarios below are in the activity instructions, but you can choose to present students with several additional scenarios to illustrate, such as a car going around a corner or a cannon ball being fired out of a cannon.

Spacecraft in Orbit

The spacecraft moves in a circular path around the Earth. Its velocity vector is constantly changing, even if its speed is constant. The acceleration vector arrow points towards the center of the Earth, in the same way the force due to gravity would act.

Car Slowing Down

The velocity arrow changes as the car slows down. The direction of the arrow remains constant, in the direction the car is moving. The size of the velocity arrow decreases as the car gets slower. The acceleration arrow acts in the opposite direction to the velocity arrow. This is known as negative acceleration or deceleration.

Ball Thrown in the Air

The velocity vector points in the direction of travel and changes as the ball follows its path. The acceleration vector arrow remains constant as the ball is in the air. The arrow points directly downwards towards the Earth.