Answer:
Explanation:
400 W = 400 J/s
300000 J / 400 J/s = 750 s or 12.5 minutes
The height of the object will be -5.19 cm
A concave mirror's reflecting surface curves inward and away from the light source. Light is reflected inward to a single focus point via concave mirrors. Concave mirrors, in contrast to convex mirrors, produce a variety of images depending on the object's to the mirror.
Given an object 24.0 cm from a concave mirror creates a virtual image at -33.5 cm. if the image is 7.25 cm tall
So let,
v = Image distance from the mirror = -33.5 cm
u = object distance from the mirror (concave) = 24 cm
hi = Image height = 7.25 cm
h = height of the object = ?
Using below formula to find height of the object
-v/u = hi/h
Putting all value in the formula we get
-(-33.5)/(-24) = 7.25/h
h = -5.19 cm
Therefore the height of the object will be -5.19 cm
Learn more about Concave mirror here:
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I would say A Because it weighs more than the water
<u>Yes, work is done when a book falls of the table.</u>
This is because:
When the book falls, it's potential energy is converted into kinetic energy. As it reaches the floor down, this kinetic energy is converted to heat energy and sound energy due to the impact.
When a force is imposed on an object to cause displacement of that object, work is done on that object. For a force to do work on an object, there should be a displacement and this force should cause the displacement. So here, since the book falls from the table and causes the displacement of the book from the table to the floor. It is said that work is done.
Work can be given by the formula:
W = F • d
where F is the force and d is the displacement.