Answer:
50J
Explanation:
At the top you have(A)
KE_a = O
PE_a = 100J
KE + PE = 100J
At the bottom you have (C)
KE_c= 100J
PE_c=0J
KE+PE = 100J
At point C:
You are at half the height.
We know that at H, PE =100J
PE_c = mgH
At C,
PE_c= mg (H/2) *at half the height
*m and g stay the same
Intuitively, the higher you are, the more potential energy you have.
If you decrease the height by a half, your PE will also decrease
At A:
PE_a / (mg) = H
At B:
PE_b / (mg) = H/2
to also get H on the right hand side, multiply by 2
2 (PE_b/ (mg))= H
2PE_b / (mg) = H
Ok, now that we have set up 2 equations (where H is isolated), find PE at B
AT A = AT B *This way you are saying that H = H (you compare both equations)
PE_a / (mg) = 2x PE_b / (mg)
*mg are the same for both cancel them (you can do that because of the = sign)
PE_a = 2PE_b
We know that PE_a = 100J
100J/2 = PE_b
PE at b = 50J
**FIND KE at b
We know that
KE_b + PE_b is always 100J
100J = 50J + KE_b
KE_b = 50J
Answer:
We could make a frictionless generator.
Explanation:
This would change life by making the cost for energy next to zero
Answer:
Force
If you're taking classical physics, simply stated, a force is a push or a pull of some sort. But there is one other very important thing to understand about Force. A true Force is always an interaction (at least from a classical perspective). That means that forces always come in pairs. This is stated in Newton's Third Law (equal and opposite forces). Every action must have a reaction. This is required for all true forces. Another consequence of this is that force is a vector, meaning it has a magnitude and a direction. The action and reaction will always be opposite in direction.
A lot of people will say F=ma. This is true. However, it is important to keep in mind that this definition is a calculational tool. It is more precise to say the Sum of all forces=ma. The point is that ma is not a force. Forces are things like weight, tension, normal, friction, gravity, electrostatic, magnetic, and various other applied forces. The sum of forces on an object equals the product of its mass times its acceleration.
It is important to keep in mind that the force is on the object that accelerates. Another way to state this is that objects cannot accelerate themselves. You cannot push yourself back (or forwards). But if you push a heavy object like a desk forwards, then the desk can push you back.
Energy
There are many kinds of energy. There are two important things to know.
Energy is the ability to do work. It doesn't mean work is being done, but that work can be done. (So you can see there is an intimate relationship between work and energy).
Energy is conserved. That means the total amount of energy is always constant. If the energy is a system changes somehow, that means some work was done in order to move the energy from one system to another.
Energy is also a scalar (given that Work is a scalar).
I am pretty sure the answer is C.
I included things
Hope this helps!
