If you write down the formula for friction, you will get an answer.
Ff = u * N Where N is a push down force that an object experiences.
u (mu) is a constant and has no units
It may not be accelerating and still experience friction. A is not correct.
Color and Density will not affect the frictional force. B is not so.
Buoyant forces are a different thing altogether. Generally friction has nothing to do with them. C is incorrect.
The last one is your answer. Technically mg should be the answer and not mass, but the second part is correct.
Explanation:
The force of the roller-coaster track on the cart at the bottom is given by :
, m is mass of roller coaster
Case 1.
R = 60 m v = 16 m/s

Case 2.
R = 15 m v = 8 m/s

Case 3.
R = 30 m v = 4 m/s

Case 4.
R = 45 m v = 4 m/s

Case 5.
R = 30 m v = 16 m/s

Case 6.
R = 15 m v =12 m/s

Ranking from largest to smallest is given by :
F>E>A=B>C>D
Answer:Although the nervous system is very complex, nervous tissue consists of just two basic types of nerve cells: neurons and glial cells Neurons are the structural and functional units of the nervous system They transmit electrical signals, called nerve impulses. Glial cells provide support for neurons.
Explanation:
Answer: 9*10^15 N
Force=kqq/r^2
F=[(9*10^9)(1)(1)]/.001^2=9.0*10^15
We know that either team is winning which means that the cumulative forces (sum of each girl force) on both teams are equal.
This means,

being x the force of the fourth girl on the east team.
Solving to x, you get

The fourth girl on the east is pulling with a force of 220N.