We want to find the combined volume of 3 tennis balls. We will get that the combined volume is 493.7 cm^3
First, remember that for a sphere of diameter D, the volume is:

Where 3.14 is pi.
Here we know that the average diameter of a tennis ball is 6.8cm, then we can replace that in the above equation to find the volume (in average) of a single tennis ball:

Now, in 3 balls of tennis, the combined volume will be 3 times the above one, this is:

If you want to learn more about volumes, you can read:
brainly.com/question/10171109
Answer:
The observer sees the space-probe 9.055m long.
Explanation:
Let
be the length of the space-probe when measured at rest, and
be its length as observed by an observer moving at velocity
, then

Now, we know that
and
, and putting these into
we get:


Thus, an observer moving at 0.95c observes the space-probe to be 9.055m long.
Answer:
Explanation:
Given
Force of repulsion between two charge particle is given by force F
Electrostatic force is given by

where
and
is the charges of particle
r=distance between charge particle
when charges are doubled and distance is reduced to half
i.e. q become 2 q and r becomes 0.5 r


