Question

why do we say a car accelerates when it goes around a corner at a constant velocity of 20 mph?
the car is accelerating because its changing direction
the car is accelerating because of the velocity is constant
cars always accelerate when they are in motion
the car accelerates because its going 20 mph

Explanation:

To determine the correct answer, we analyze the concept of acceleration. Acceleration is defined as the rate of change of velocity. Velocity is a vector quantity, meaning it has both magnitude (speed) and direction. When a car goes around a corner at a constant speed (20 mph), its direction is changing. Since velocity depends on direction, a change in direction means a change in velocity. By the definition of acceleration (change in velocity over time), a change in velocity (even if speed is constant) results in acceleration.

• Option 1: "The car is accelerating because it’s changing direction" is correct because a change in direction (part of velocity) means a change in velocity, leading to acceleration.
• Option 2: A constant velocity would mean no acceleration, so this is incorrect.
• Option 3: Cars in motion at constant speed and direction do not accelerate, so this is incorrect.
• Option 4: Going at a constant speed (20 mph) with no direction change would not be acceleration, so this is incorrect.

Answer:

A. The car is accelerating because it’s changing direction