GK
PHYSICS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Negative Acceleration, Positive Velocity
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Positive Acceleration, Positive Velocity
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Positive Acceleration, Negative Velocity
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Negative Acceleration, Negative Velocity
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Detailed explanation-1: -Assuming rightward is positive, the velocity is positive whenever the car is moving to the right, and the velocity is negative whenever the car is moving to the left. The acceleration points in the same direction as the velocity if the car is speeding up, and in the opposite direction if the car is slowing down.
Detailed explanation-2: -When a car is slowing down, the acceleration and velocity are in opposite directions. The acceleration is negative.
Detailed explanation-3: -According to our principle, when an object is slowing down, the acceleration is in the opposite direction as the velocity. Thus, this object has a negative acceleration. In Example D, the object is moving in the negative direction (i.e., has a negative velocity) and is speeding up.
Detailed explanation-4: -If acceleration has the opposite sign as the velocity, the object is slowing down.
Detailed explanation-5: -If an object is slowing down, then the direction of its acceleration is opposite the direction which the object is moving. A rightward moving object which is slowing down has a leftward acceleration. And a leftward moving object which is slowing down has a rightward acceleration.