Answer: The law of conservation of energy is a physical law that states energy cannot be created or destroyed but may be changed from one form to another. Another way of stating this law of chemistry is to say the total energy of an isolated system.
Explanation:
The magnitude of a vertical electric field that will balance the weight of a plastic sphere of mass 2. 1 g that has been charged to -3. 0 NC is 6.86 ×
N/C.
An electric field is the physical field that surrounds electrically charged particles and exerts a force on all other charged particles in the field, either attracting or repelling them. It also refers to the physical field of a system of charged particles.
It is given that,
Mass of sphere, m = 2.1 g =0.0021kg
Charge,q = ₋3nC = ₋ 3 ₓ 
To balance the weight of a plastic sphere, we must determine the magnitude of the electric field. So,

a = g

E = 
E = 6860000 N/C
E = 6.86 ×
N/C
Hence, the magnitude of the electric field that balances its weight is 6.86 ×
N/C .
To know more about electric field refer to: brainly.com/question/8971780
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210J
PE is mgh in this context.
Answer:
Explanation:
From the 1st Law of linear motion which states that when a body goes into motion, it will continue doing so until it is stopped by force. So the body of the rider keeps moving until it is been stopped and the stopping could be as a result of an impact of any part of the body which includes the head it an object. Also the 3rd Law of Motion will also be applicable because for every action, there will be equal and opposite reaction. The magnitude of the impact will be as a result of the force with which the crash took place as well.
When crashes take place the rider does not always experience a head impact square on with a solid obstruction. During a bike crash, your head comes in contact with the ground. The ground exerts a force that causes your head to stop moving. Often impact will be at an angle and may not be head first. It may be your shoulder will hit first, then your side, and then your head will receive a glancing blow against the ground as you slide.
The ground exerts so much force that it can stop our forward motion within seconds. Without your motorcycle helmet, your head experiences a huge amount of concentrated force during a crash.
You can start this by setting up two vectors starting at the origin.
Vector 1 has coordinates of (-57,0) since in the east direction.
Vector 2 has coordinates of (0,13) because going north.
Starting from the origin, plot the two points, which will give you two sides of a triangle.
You can use pythagorean theorem to solve for the magnitude of the velocity. And you can find the angle by arctan(y/x)
Pythagorean would produce 58.46m/s