How fast a car goes is known as its speed.
Speed = (distance covered) divided by (time to cover the distance)
It has nothing to do with the direction the car is going.
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The car's velocity is its speed AND the direction it's going.
30 miles per hour . . . speed
40 miles per hour north . . . velocity
20 miles per hour south
20 miles per hour west . . . . . same speed, different velocity
-- 'Velocity' is NOT a big word that you use when you mean
'speed' but you want to sound smarter. It's a different thing.
-- If you don't know anything about the direction the car is going,
then you can't say anything about its velocity.
-- If the car is going around a curve, then its velocity is constantly
changing, even if its speed is constant.
At the present time, the only way we know of that light can get shifted
toward the blue end of the spectrum is the Doppler effect ... wavelengths
appear shorter than they should be when the source is moving toward us.
IF that's true in the case of the Andromeda galaxy, it means the galaxy is
moving toward us.
We use the same reasoning to conclude that all the galaxies whose light is red-shifted are moving away from us. That includes the vast majority of all galaxies that we can see, and it strongly supports the theory of the big bang
and the expanding universe.
If somebody ever comes along and discovers a DIFFERENT way that light
can get shifted to new, longer or shorter wavelengths, then pretty much all
of modern Cosmology will be out the window. There's a lot riding on the
Doppler effect !
The emerging velocity of the bullet is <u>71 m/s.</u>
The bullet of mass <em>m</em> moving with a velocity <em>u</em> has kinetic energy. When it pierces the block of wood, the block exerts a force of friction on the bullet. As the bullet passes through the block, work is done against the resistive forces exerted on the bullet by the block. This results in the reduction of the bullet's kinetic energy. The bullet has a speed <em>v</em> when it emerges from the block.
If the block exerts a resistive force <em>F</em> on the bullet and the thickness of the block is <em>x</em> then, the work done by the resistive force is given by,
This is equal to the change in the bullet's kinetic energy.
If the thickness of the block is reduced by one-half, the bullet emerges out with a velocity v<em>₁.</em>
Assuming the same resistive forces to act on the bullet,
Divide equation (2) by equation (1) and simplify for v<em>₁.</em>
Thus the speed of the bullet is 71 m/s
The force of attraction or repulsion between two charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them and acts along the line joining the two charges . F=k Q1Q2/r^2
Answer:
Option C
Explanation:
The graph shows endothermic reaction because the reactants are lower in energy and the products are higher is energy. Endothermic reactions absorb energy having products with higher energy.
