True or False? (a) A car must always have an acceleration in the same direction as its velocity. —Select— (b) It’s possible for a slowing car to have a positive acceleration. —Select— (c) An object with constant nonzero acceleration can never stop and remain at rest. —Select—
The Correct Answer and Explanation is :
Here are the correct answers and explanations for each statement:
(a) A car must always have an acceleration in the same direction as its velocity.
Answer: False
Explanation:
Acceleration and velocity do not always have to point in the same direction. Acceleration is the rate of change of velocity, and it can occur in any direction relative to the object’s velocity. If a car is slowing down, its acceleration is actually in the opposite direction of its velocity (this is often referred to as deceleration or negative acceleration). For example, if a car is moving forward but slowing down, the acceleration would be in the backward direction.
(b) It’s possible for a slowing car to have a positive acceleration.
Answer: True
Explanation:
The concept of “positive” or “negative” acceleration depends on the chosen frame of reference. If we define forward motion as positive, then a car slowing down while moving in reverse can have a positive acceleration, even though it’s slowing down. In other words, acceleration is positive when the velocity increases in the positive direction or decreases in the negative direction. So, a car slowing down while moving backward (negative velocity) but with a “positive” acceleration is possible if we’re considering forward motion as positive.
(c) An object with constant nonzero acceleration can never stop and remain at rest.
Answer: True
Explanation:
An object experiencing constant nonzero acceleration means that its velocity is continuously changing. If it stops momentarily, it cannot remain at rest because acceleration implies a change in velocity. A constant nonzero acceleration will always push the object to continue moving. If an object stops (velocity reaches zero) but the acceleration is still nonzero, the object will immediately start moving again in the direction dictated by the acceleration. Therefore, it can’t remain at rest under these conditions.