The waves with the lowest energy and lowest frequencies of the electromagnetic spectrum are the
1 answer:
You might be interested in
1) 9.26 cm
Explanation:
The focal length of a plane mirror is virtually infinite. Considering the lens equation,
where f is the focal length, p is the object distance, q the image distance. If we replace f with infinity, we get
The magnification equation states that
where y is the size of the object and y' the size of the image. Substituting q=-p, we get
this means that the image produced by a plane mirror is always:
- Upright (y' is positive)
- The same size as the object
In this case, we have a book of height 9.26 cm (y=9.26 cm). This means that the magnitude of the size of the image (y') will be 9.26 cm as well.
2) 22.7 cm
As we said before, due to the infinite focal length of a plane mirror,
this means that the image produced by a plane mirror is always:
- Virtual (because q is negative)
- At the same distance from the mirror as the object
In this case, we have a book placed at 22.7 cm from the mirror (p=22.7 cm). This means that the magnitude of the distance of the image from the mirror (q) will be 22.7 cm as well.
3) 1.60 m/s
We said previously that the image produced by a plane mirror is always at the same distance from the mirror as the real object. This implies that whenever we move the object toward/away from the mirror, the distance p will alway remain equal to the distance q. But this also means that the object and the distance are moving toward/away from the mirror at the same speed.
Therefore, since in this case the person is moving away from the mirror at 1.60 m/s, the image will also move away at a speed of 1.60 m/s.
Answer:
v= 14.85 m/s
Explanation:
- When at the bottom of the dip, the only force that keeps the car in the circular trajectory, is the centripetal force.
- This force is not a new force, is just the net force aiming to the center of the circle.
- In this case, is just the difference between the normal force (always perpendicular to the surface, pointing upward) and the force that gravity exerts on the car (which is known as the weight), pointing downward.
- So, we can write the following expression:
- It can be showed that the centripetal force is related to the speed by the following expression:
- The normal force, it is called the apparent weight, because it would be the weight as measured by a scale.
- Replacing (2) in (1), and solving for Fn, we get:
- Now, we need to find the value of v that makes Fn, exactly 15% more than the weight m*g, so we can write the following equation:
- Replacing Fg by its value, simplifying, and solving for v, we get: