Nothing happens to the mirror.
However, if the ray is within some suitable range of
wavelengths, the ray is reflected from the mirror's surface.
First we will find the speed of the ball just before it will hit the floor
so in order to find the speed of the cart we will first use energy conservation



So by solving above equation we will have

now in order to find the momentum we can use



1) The mass of the continent is 
2) The kinetic energy of the continent is 1683 J
3) The speed of the jogger must be 6.57 m/s
Explanation:
1)
The continent can be represented as a slab of size

and depth

So its volume is

We also know that the density of the continent is

Therefore, we can calculate its mass as:

2)
The kinetic energy of the continent is given by

where
m is its mass
v is its speed
We have already calculate its mass, while the speed is
v = 3.2 cm/year
We have to convert into SI units first, as follows:

The mass is

So, the kinetic energy of the continent is

3)
Here we have a jogger having the same kinetic energy of the continent, so

And the kinetic energy of the jogger can be expressed as

where
m = 78 kg is the mass of the jogger
v is his speed
We can therefore re-arrange the equation to find the speed of the man, and we get:

Learn more about kinetic energy:
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Answer:
B
Explanation:
Acceleration = rate of change in velocity
a = (21-12)/(0.45) = 20cm/s^2
To calculate the volume of the diamond, we use the formula

Here,
is the density and its value given 
and m is mass and its value given
.
1 carat = 200 mg = 0.200 g
So mass of the diamond, 
Substituting these values in above equation we get,

Thus the volume of given carat diamond is
.