Answer:
a) 
Explanation:
a) Let assume that the ground is not inclined, since the bottom of the playground slide is tangent to ground. Then, the length of given by the definition of a circular arc:



The bottom of the slide has a height of zero. The physical phenomenon around Dr. Ritchey's daughter is modelled after Principle of Energy Conservation. The child begins at rest:


The average frictional force is cleared within the expression:

![f = \frac{(12\,kg)\cdot [(9.807\,\frac{m}{s^{2}} )\cdot (3\,m)-\frac{1}{2}\cdot (4.5\,\frac{m}{s} )^{2} ]}{6.676\,m}](https://tex.z-dn.net/?f=f%20%3D%20%5Cfrac%7B%2812%5C%2Ckg%29%5Ccdot%20%5B%289.807%5C%2C%5Cfrac%7Bm%7D%7Bs%5E%7B2%7D%7D%20%29%5Ccdot%20%283%5C%2Cm%29-%5Cfrac%7B1%7D%7B2%7D%5Ccdot%20%284.5%5C%2C%5Cfrac%7Bm%7D%7Bs%7D%20%29%5E%7B2%7D%20%5D%7D%7B6.676%5C%2Cm%7D)

Answer:
B - Person A's chair rolls backwards.
Explanation:
This can be seen simply through the Conservation of Momentum. When the ball is thrown to be, the ball's momentum(+m) is transfererd to B, so B's chair moves forward(think about it - it makes sense, doesn't it?), meaning A's chair moves backwards.
So, B.
EXTRA TIP: Try drawing a diagram to help you!
Answer:
When the parachute opens, the air resistance increases. The skydiver slows down until a new, lower terminal velocity is reached.
B
paired electrons spin in opposite directions cancelling their magnetic fields