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1 answer:
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.
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Answer:
here
Explanation:
The given from your problem are the following:
V = 85mph (This is miles per hour)
d = 60 feet
If you notice the units do not match. Before we can do anything else, we need to make the figures match.
In this case, we will convert 85miles per hour to feet per hour. There are 5,280 feet in 1 mile.
x 
But wait! If you think about the scenario, you are looking for how long it will take for the ball to reach the bat. The most applicable unit of time to use here is second. It would be very hard to really measure a short and instantaneous event in hours. So we convert it into feet per second:
There are 3,600 seconds in 1 hour.
x 
So now we have our new given as:
v = 124.67ft/s
d = 60 ft
The formula for time can be derived from the formula from velocity, which is:
The formula of time will then be:
All you need to do is plug in what you know and solve for what you don't know.
The answer then is 0.48s.
If you want this in hours, just divide the value in seconds by 3,600. The answer would then be 0.00013hr. (See how small it is? This is why seconds would be a more appropriate measure.)
V = 85mph (This is miles per hour)
d = 60 feet
If you notice the units do not match. Before we can do anything else, we need to make the figures match.
In this case, we will convert 85miles per hour to feet per hour. There are 5,280 feet in 1 mile.
But wait! If you think about the scenario, you are looking for how long it will take for the ball to reach the bat. The most applicable unit of time to use here is second. It would be very hard to really measure a short and instantaneous event in hours. So we convert it into feet per second:
There are 3,600 seconds in 1 hour.
So now we have our new given as:
v = 124.67ft/s
d = 60 ft
The formula for time can be derived from the formula from velocity, which is:
The formula of time will then be:
All you need to do is plug in what you know and solve for what you don't know.
The answer then is 0.48s.
If you want this in hours, just divide the value in seconds by 3,600. The answer would then be 0.00013hr. (See how small it is? This is why seconds would be a more appropriate measure.)