Answer:
The answer to your question is below
Explanation:
To explain what happens with the ball we must remember the Law of Conservation of Energy.
This law states that the energy can be neither created nor destroyed only converted from one form of energy to another.
Then,
At the top of the hill, the potential energy is maximum and the kinetic energy equals to zero.
When the ball starts to roll down the potential energy will be lower and the kinetic energy will have a low value.
At the middle of the hill, both energies have the same values.
At the end of the hill, the potential energy will be equal to zero and the kinetic energy will be maximum.
Answer:
40g
Explanation:
Solubility of Copper sulfate at 90°=60g
Solubility of potassium bromide at 90°=100g
100g-60g=40g
Let car A's starting position be the origin, so that its position at time <em>t</em> is
A: <em>x</em> = (40 m/s) <em>t</em>
and car B has position at time <em>t</em> of
B: <em>x</em> = 100 m - (60 m/s) <em>t</em>
<em />
They meet when their positions are equal:
(40 m/s) <em>t</em> = 100 m - (60 m/s) <em>t</em>
(100 m/s) <em>t</em> = 100 m
<em>t</em> = (100 m) / (100 m/s) = 1 s
so the cars meet 1 second after they start moving.
They are 100 m apart when the difference in their positions is equal to 100 m:
(40 m/s) <em>t</em> - (100 m - (60 m/s) <em>t</em>) = 100 m
(subtract car B's position from car A's position because we take car A's direction to be positive)
(100 m/s) <em>t</em> = 200 m
<em>t</em> = (200 m) / (100 m/s) = 2 s
so the cars are 100 m apart after 2 seconds.
If the angle is either 0 or 180, that means that there is either negative or positive work, so A and D are not correct.
If the angle is 45, then there is still some work involved.
The only option where there is no work done by a force is B. when the angle is between the force and displacement is 90.
