To solve this problem we will resort to the concept of angle of incidence and refraction.
Since it is a reflection on a mirror, the angle provided for refraction will be equal to that of the incidence, that is, 25 °
The angle of reflation is always perpendicular to the surface so it is necessary to find the angle with respect to it.
Therefore the angle of the reflected beam of light made with the surface normal is 65°
The diagram is missing; however, we know that the intensity of a sound wave is inversely proportional to the square of the distance from the source:
where I is the intensity and r is the distance from the source.
We can assume for instance that the initial distance from the source is r=1 m, so that we put
The intensity at r=3 m will be
Therefore, the sound intensity has decreased by a factor
.
Answer:
a)
b)
c)
d)
Explanation:
Given:
- length of muscle fibers,
- maximum stress on each fiber,
- Volume of muscles,
<em>∴Area of the muscle:</em>
a)
Maximum force developed by this muscle:
b)
Force when the muscles are 10% activated:
c)
- contraction in length of muscle,
- time taken for the contraction,
<u>Now, the speed of the muscle:</u>
d)
<u>Maximum force delivered when the muscle fibers are oriented at 15° from the tendons:</u>
Answer:a substance with low ability or no ability to conduct energy
Explanation: