Why is work measured in
1 answer:
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Answer:
B) The car at point C has less kinetic energy than the car at point B.
Explanation:
We have two types of energy involved in this situation:
- Gravitational potential energy: this is the energy related to the heigth of the car, and it is given by , where m is the mass of the car, g is the gravitational acceleration, and h is the heigth of the car. The potential energy is higher when the car is located higher above the ground.
- Kinetic energy: this is the energy due to the motion of the car, and it is given by , where m is the mass of the car and v is its speed. The kinetic energy is higher when the speed of the car is higher.
- The law of conservation of energy states that the total mechanical energy of the car (sum of potential energy and kinetic energy: ) is constant). This implies that when the car is at a higher point, the kinetic energy is less (because U is larger, so K must be smaller), while when the car is at a lower point, the kinetic energy is larger.
- Based on what we have written so far, we can conclude that the correct statement is:
B) The car at point C has less kinetic energy than the car at point B.
Because the car at point C is located at a higher point than point B, so the car at point C has larger potential energy than at point B, which implies that car at point C has less kinetic energy than the car at point B.
Answer:
b) the refracted ray has an angle of 90 degrees
Explanation:
The angle of incidence is measured with respect to the normal separation of the media. The critical angle for total internal reflection occurs is:
Here and
are the refractive index of the mediums. This equation is an application of Snell's law, for the case where the refracted ray has an angle of
.
Answer:
Explanation:
At the corner of the square, the potential energy of interaction of other charges with the charge 2q is given by
So
Also, since
The initial energy of the system is given by;
Since
, the final energy of the system is obtained by
From the law of conservation of energy,
Therefore,