The answer would be option D "a ball sitting on a shelf." Potential energy is the amount of energy a object has while it's at rest.. (or not moving) Kinetic energy is how much energy a object is while it's moving. So in this case it's option D because a ball sitting on a shelf isn't moving therefore it has potential energy. It's not option A because thats a example of kinetic energy since how the roller coaster is moving. It's not option B because it's kinetic energy because the bike is moving. It's also not option C because it's kinetic energy because the bird is moving.
Hope this helps!
These are known as balanced forces because they will not change the motion of the object, and it will remain at rest unless forces become unbalanced- meaning they would be unequal and not opposing.
Answer:
a) 
b) 
c) 
Explanation:
the gravitational potential energy is given by:
The kinetic energy is given by:
the initial kinetic energy is zero because the motion started from rest, so:
applying the conservation of energy theorem:
The work done by the friction force is given by:
the angle of the force is 180 degrees because it's against the movement:
Answer:
b)determining the electric field due to each charge and adding them together as vectors.
Explanation:
The electric Field is a vector quantity, in other words it has a magnitude and a direction. On the other hand, the electric field follows the law of superposition. The electric field produced by two elements is equal to the sum of the electric fields produced by each element when the other element is not present. in other words, the total electric field is solved determining the electric field due to each charge and adding them together as vectors.
