Difference between solid friction and viscosity is as follows: Viscosity is proportional to the surface area whereas solid friction is independent of area of solid surfaces in contact. Viscous force on the body depends upon its velocity in the viscous media. But, friction does not depend on the velocity of the body.
Answer:
B
Explanation:
The correct answer is B) have unlike charges. Since they are attracted to each other they have to be unlike
If the kinetic energy of each ball is equal to that of the other,
then
(1/2) (mass of ppb) (speed of ppb)² = (1/2) (mass of gb) (speed of gb)²
Multiply each side by 2:
(mass of ppb) (speed of ppb)² = (mass of gb) (speed of gb)²
Divide each side by (mass of gb) and by (speed of ppb)² :
(mass of ppb)/(mass of gb) = (speed of gb)²/(speed of ppb)²
Take square root of each side:
√ (ratio of their masses) = ( 1 / ratio of their speeds)²
By trying to do this perfectly rigorously and elegantly, I'm also
using up a lot of space and guaranteeing that nobody will be
able to follow what I have written. Let's just come in from the
cold, and say it the clear, easy way:
If their kinetic energies are equal, then the product of each
mass and its speed² must be the same number.
If one ball has less mass than the other one, then the speed²
of the lighter one must be greater than the speed² of the heavier
one, in order to keep the products equal.
The pingpong ball is moving faster than the golf ball.
The directions of their motions are irrelevant.
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:
![V = \frac{4}{3}*3.14*(\frac{D}{2})^3](https://tex.z-dn.net/?f=V%20%3D%20%5Cfrac%7B4%7D%7B3%7D%2A3.14%2A%28%5Cfrac%7BD%7D%7B2%7D%29%5E3)
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:
![V = \frac{4}{3}*3.14*(\frac{6.8cm}{2})^3 = 164.5 cm^3](https://tex.z-dn.net/?f=V%20%3D%20%5Cfrac%7B4%7D%7B3%7D%2A3.14%2A%28%5Cfrac%7B6.8cm%7D%7B2%7D%29%5E3%20%3D%20164.5%20cm%5E3)
Now, in 3 balls of tennis, the combined volume will be 3 times the above one, this is:
![3*V = 3*164.5cm^3 = 493.7 cm^3](https://tex.z-dn.net/?f=3%2AV%20%3D%203%2A164.5cm%5E3%20%3D%20493.7%20cm%5E3)
If you want to learn more about volumes, you can read:
brainly.com/question/10171109