Answer:
a) The current is i = 1.2 A
b) The charge is Q = 17280 C
c) The energy is E = 43200 J
Explanation:
a) The current is given by the ohm's law wich is:
i = V/R = 3/2.5 = 1.2 A
b) Since the charge is steady we can use the following equation to find the charge amount in that time:
i = Q/t
Q = t*i
Where t is in seconds, so we have 4h * 3600 = 14400 s
Q = 1.2*14400 = 17280 C
c) The energy is the power delivered to the toy multiplied by the time:
P = 1.2*2.5 = 3 W
E = P*t = 3*14400 = 43200 J
Answer:
The kinetic energy is 1200 J
Explanation:
The Principle of Conservation of energy states that "energy is neither created nor destroyed, it is transformed".
This means that energy can be transformed from one form to another, but the total amount of energy always remains constant, that is, the total energy is the same before and after each transformation.
The mechanical energy of a body or a physical system is the sum of its kinetic energy and the potential energy. According to the Principle of Conservation of Energy for mechanical energy, the total mechanical energy that a body possesses is constant at every instant of time.
Since mechanical energy is equal to the sum of kinetic energy and gravitational potential energy that a body possesses, the only way to stay constant is that:
- when the kinetic energy increases the gravitational potential energy decreases,
- when gravitational potential energy increases, kinetic energy decreases.
Due to the Principle of Conservation of Energy you can say that the gravitational potential energy is converted to kinetic energy. So Gravitational potential energy at the top = kinetic energy at the bottom
<u><em>The kinetic energy is 1200 J</em></u>
If no frictional work is considered, then the energy of the system (the driver at all positions is conserved.
Let
position 1 = initial height of the diver (h₁), together with the initial velocity (v₁).
position 2 = final height of the diver (h₂) and the final velocity (v₂).
The initial PE = mgh₁ and the initial KE = (1/2)mv₁²
where g = acceleration due to gravity,
m = mass of the diver.
Similarly, the final PE and KE are respectively mgh₂ and (1/2)mv₂².
PE in position 1 is converted into KE due to the loss in height from position 1 to position 2.
Therefore
(KE + PE) ₁ = (KE + PE)₂
Evaluate the given answers.
A) The total mechanical energy of the system increases.
FALSE
B) Potential energy can be converted into kinetic energy but not vice versa.
TRUE
C) (KE + PE)beginning = (KE + PE) end.
TRUE
D) All of the above.
FALSE
Answer:
Newton's First Law of Motion applies here.
Explanation:
Before crashing into the fence, Amy was moving at a certain speed on her bike. As, she crashed her bike into the fence, the collision stopped the bike suddenly. But, Amy had the same speed due to inertia of her body. Due tot his speed Amy did not stop and she was thrown over the fence onto the lawn. So, the force of inertia of Amy's body caused her to be overthrown in this case. We study about inertia in Newton's First Law of Motion, which is also known as Law of Inertia.
<u>Newton's First Law of Motion applies here.</u>