Answer:
A)
B) 
Explanation:
Using the free body diagram and according to Newton's first law, we have:

A) Solving (1) for T:

B) Solving (2) for F:

Answer:
B
Explanation:
a straight yellow is a no pass zone
The particle has constant acceleration according to

Its velocity at time
is



Then the particle has position at time
according to


At at the point (3, 6, 9), i.e. when
, it has speed 8, so that

We know that at some time
, the particle is at the point (5, 2, 7), which tells us

and in particular we see that

and

Then



That is, there are two possible initial velocities for which the particle can travel between (3, 6, 9) and (5, 2, 7) with the given acceleration vector and given that it starts with a speed of 8. Then there are two possible solutions for its position vector; one of them is

Answer:
People have been aware of magnets and magnetism for thousands of years. The earliest records date back to ancient times, particularly in the region of Asia Minor called Magnesia-the name of this region is the source of words like magnet. Magnetic rocks found in Magnesia, which is now part of western Turkey, stimulated interest during ancient times. When humans first discovered magnetic rocks, they likely found that certain parts of these rocks attracted bits of iron or other magnetic rocks more strongly than other parts. These areas are called the poles of a magnet. A magnetic pole is the part of a magnet that exerts the strongest force on other magnets or magnetic material, such as iron. For example, the poles of the bar magnet shown in Figure 20.2 are where the paper clips are concentrated.
Answer:
D. moving slow at a constant speed and traveling along a straight line