On a 8 question multiple-choice test, where each

In a truck-loading station at a post office, a small 0.200-kg package is released from rest a point A on a track that is one quarter of a circle with radius 1.60 m.The size of the packageis much less than 1.60m, so the package can be treated at aparticle. It slides down the track and reaches point B with a speed of 4.80 m/s. From point B, it slides on a level surface a distanceof 3.00 m to point C, where is comes to rest. 
(a) What is the coefficient of kinetic friction on the horizontal surface? 
(b) How much work is done on the package by friction as it slides down the circular arc from A to B?

Write in words how to read each of the following out loud.
a. ${\displaystyle \{x\in R^{\prime }\mid 0<x<1\}}$
b. ${\displaystyle \{x\in R\mid x\le 0\text{or}x\Rightarrow 1\}}$
c. ${\displaystyle \{n\in Z\mid nisafactorof6\}}$
d. ${\displaystyle \{n\in Z\cdot \mid nisafactorof6\}}$

Two blocks with masses 4.00 kg and 8.00 kg are connected by string and slide down a 30.0 degree inclined plane. The coefficient of kinetic friction between the 4.00-kg block and the plane is 0.25; that between the 8.00-kg block and the plane is 0.35.
a) Calculate the acceleration of each block
b) Calculate the tension in the string
c) What happens if the positions of the block are reversed, so that the 4.00-kg block is above the 8.00-kg block?

A 0.50 kg ball that is tied to the end of a 1.1 m light cord is revolved in a horizontal planewith the cord making a ${\displaystyle {30}^{\circ }}$ angle, with the vertical.

a) Determine the ball speed.
b) If, instead, the ball is revolved so that its speed is 4.0 m/s,what angle does the cord make with the vertical?
c) If the cord can withstand a maximum tension of 9.1 N, what is the highest speed at which the ballcan move?