Imagine an object is moving in one dimension on a number line, and for this we'll say that the numbers on the line are a metre apart. If the object moves from 2 m to 7 m, the change in position is 7-2=+5 metres. But if the object moves back from 7 m to 2 m, the change in position is 2-7=-5 metres. since

, and time is always positive, velocity will be positive in one direction and negative in the other direction.
Hi!
The answers would be <u>chunking</u> & <u>short-term</u>
1. <u>Chunking </u>involves organizing and breaking down information into easier groups to expand capacity.
<h3>Explanation:</h3>
Chunking is a mental process that is observed to increase short-term memory by taking the information and categorizing it into small groups. For instance, a longer number taken as a single unit is harder to recall then when it is divided into smaller units. 235469350 is harder to instantly recall as compared to when it is chunked into 3 groups: 235 469 350.
This allows more information to be stored in, thereby increasing the capacity of the mind to store information.
2. Rehearsal is the verbal repetition of information. These techniques are especially important for the improvement of <u>short-term</u> memory.
<h3>Explanation: </h3>
Short-term memory is lost after a couple of seconds or minutes, for instance even if you chunk the information, you might not recall it after 30 seconds. Rehearsing or repetition of information, either loudly or mentally, extends the time a particular information is retained.
So you depending on the number of times you repeat the number 235 469 350, the more your short term memory improves .
Hope this helps!
Answer:
a. Doppler and transit observations.
Explanation:
By means of the dopler effect, the radial velocity of an extrasolar planet can be measured, this is achieved by observing Doppler shifts in the spectrum of the star around which the planet orbits. This measure, combined with the transit observations, makes possible determine the density of the planet.
We know, length of segment wave is half the wavelength .
Let, wavelength of wave is
.
So, length of segment will be
.
Now, it is given that the string vibrates in four segments.
So,

Speed can be given by :

Therefore, the wave speed in the string is 120 m/s.