1. Centimeter
2. Kilogram
3. Millisecond
4. DL
5. Kg
6. Mm
7. S
8. Mm
9. Us
Answer: "B" Changing Position
Great Question!
Explanation: <u><em>When a ball bounces to the ground it hits the ground with some energy. The amount of energy with which it hits the ground is kinetic energy. When it comes in the contact with the ground kinetic energy gets converted into potential energy. This potential energy again gets converted into kinetic energy and balls moves again from the ground and bounces multiple times. So, the ball ends up changing position</em></u>
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Centripetal acceleration is directed along a radius so it may also be called the radial acceleration. If the speed is not constant, then there is also a tangential acceleration (at). The tangential acceleration is, indeed, tangent to the path of the particle's motion.
Let us consider two vectors A and B.
As per the question, the two vectors are perpendicular to each other.
Hence the angle between them 
We are asked to calculate the resultant of these two vectors.
As per parallelogram law of vector addition, the resultant of two vectors are-

[cos90=0]

This is the way by which we can add two perpendicular vectors.
Fluorine has nine protons