The velocity of any object depends upon a) the location of the object. b) the location of the observer. c) which measurement tools are used. d) the relative motion of the observer.

B)The location of observer

Explanation:

Velocity: As velocity is vector measurement of the rate by which any object changes its position with time, we can calculate velocity by using the formula:

               v = d/t

v= velocity

d= displacement

t = time

EXAMPLE:

When someone travels a distance of 1500 m from his home to office and then come back from office to home at 30 minutes, what will be its velocity?

Displacement = 0

Because the person is at same position

So according to the formula the average velocity of the person is also zero

                   v = 0/30

                   v = 0

When someone travels a distance from his home to office and covers a displacement of 1500 meters at 300 seconds, what will be its average velocity?

                v = 1500 m / 300 s

                v = 5 m/s

The SI unit of velocity is m/s and it is a vector quantity.

D. The relative motion of the observer

Explanation:

From observation say an observer is stationary and an object of velocity 2m/s passes, it's quite understandable for the observer to notice the motion of the object,

Now say the observer is also moving at same speed of 2m/s, isn't it true that the observer will notice that the object is stationary? A classical example is a boy playing in a bus moving at 80km/h, it will appear to an observer in the same bus as though they are stationary, but an observer outside the bus will notice their movement.

a electronegativity decreases beacuse the size of nucleus is bigger.

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.