-- pick a planet from the table
-- take it's mass and radius from the table, and plug them into the big ugly formula above the table
-- do the arithmetic with your pencil or your calculator. The answer is the acceleration of gravity on the planet you picked. Write it down so you don't lose it.
-- do the same for the other 3 planets in the table
Answer:
The answer is based on the conservation of energy law; something you should really understand by now.
For convenience we can hold one of the two charges still; it becomes the frame of reference. And everything we say is in reference to the designated static charge, call it Q.
So the moving charge, call it q, has total energy TE = PE. It's all potential energy as we start with q not moving.
It has potential energy because in order to separate q from Q, we had to do work, add energy, on q. And from the COE law, that work added is converted into PE.
It's a bit like lifting something off the ground. That's work and it becomes GPE. So there's some work, in separating the two charges in the first place.
But there's more.
Now we let q go. As opposites attract, q is pulled to Q. And that force from Q is working on q, force over distance. Which means the potential energy q started with is being converted into kinetic energy. q is accelerating and picking up speed.
And there's more work, done by the EMF on charge q. That converts the PE into KE and the q charge smashes into Q with some kinetic energy.
Answer:
This means that the center of mass is locates 0.72m from the 750N force
Explanation:
Since the board is 2.2m long, that will be the length of the board.
Let the center of mass of the body be hinged at the center using a knife edge as shown in the diagram attached.
Let x be the distance from the 750N force to the knife edge and the distance from the 360N force to the knife edge be 2.2-x
Using the principle of moment which states that the sum of clockwise moment is equal to the sum of anti clockwise moment.
Moment = force × perpendicular distance
For ACW moment;
Moment = 750×x = 750x
For the CW moment;
Moment = 360 × (2.2-x)
Moment = 792-360x
Equating ACW moment to the clockwise moment we have;
750x = 792-360x
750x+360x = 792
1110x = 792
x = 792/1110
x = 0.72m
This means that the center of mass is locates 0.72m from the 750N force
