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:
6 second
Explanation:
initial velocity of ball, u = 60 m/s
g = 10 m/s^2
Let the ball takes time t to reach at the maximum height
We know that at maximum height, the velocity of ball is zero.
v = 0 m/s
Use first equation of motion
v = u + gt
0 = 60 - 10 x t
t = 6 second
Thus, the ball takes 6 second to reach to maximum height.
Answer:
1210 ohm
Explanation:
Given :
P=40 W
V=220 V
Now,

Therefore, resistance of bulb will be 1210 ohm