If a body moves with a constant speed and at the same time undergoes an acceleration, its motion is said to be
- A. Oscillation
- B. Circular
- C. Rotational
- D. Rectilinear
QUICK ANSWER…
B
EXPLANATION…
Speed is a scalar quantity while acceleration is a vector, acceleration depends on change in another vector called velocity, and not change in speed.
In circular motion, a body may be moving with constant speed, but the velocity will never be constant. This is because velocity is a vector that depends on both magnitude and direction. As the direction of the object moving in a circle changes, the velocity also changes even though the speed is constant. The body will also be accelerating because the velocity is changing. Remember, acceleration = change in velocity/change in time.
So, a circular motion will automatically turn a constant speed into changing velocity (because of changing direction) and by extension acceleration.
Now for the right answer to the above question:
- Option A is incorrect. not the right answer.
- Option B is correct. a circular motion will turn a constant speed into a varying velocity by virtue of its changing direction.
- C is incorrect. a rotating body like a spinning ball does not necessarily change its direction and so, does not accelerate.
- D is not the correct answer. in a rectilinear motion, constant speed would mean constant velocity because the direction is not changing.
HELPFUL TIPS…
You may please note these/this:
- In circular motion, constant speed will translate as changing velocity because the direction is changing.
- And changing velocity would mean the body is accelerating.
- Other kinds of motion do not achieve this.
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/culled from 2019 JAMB-UTME physics question 2/