Answer:
is this phsyics teacher, is he good i-
Explanation:
Answer:
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- <u>1. The potential energy of the swing is the greatest at the position B.</u>
- <u>2. As the swing moves from point B to point A, the kinetic energy is increasing.</u>
Explanation:
Even though the syntax of the text is not completely clear, likely because it accompanies a drawing that is not included, it results clear that the posittion A is where the seat is at the lowest position, and the position B is upper.
The gravitational <em>potential energy </em>is directly proportional to the height of the objects with respect to some reference altitude. Thus, when the seat is at the position A the swing has the smallest potential energy and when the seat is at the <em>position B the swing has the greatest potential energy.</em>
Regarding the forms of energy, as the swing moves from point B to point A, it is going downward, gaining kinetic energy (speed) at the expense of the potential energy (losing altitude). When the seat passes by the position A, the kinetic energy is maximum and the potential energy is miminum. Then the seat starts to gain altitude again, losing the kinetic energy and gaining potential energy, up to it gets to the other end,
Answer:
The correct prediction will be:
The temperature of the surface of the ball bearing when rubbed over glass will be the least.
The incorrect prediction:
The tennis ball over the linoleum floor will have no friction, as the temperatures will not change.
Answer:
B
Explanation:
Work done can be said to be positive if the applied force has a component to be in the direction of the displacement and when the angle between the applied force and displacement is positive.
In 1 and 2 work done is positive
The average current density in the wire is given by:

where I is the current intensity and A is the cross-sectional area of the wire.
The cross-sectional area of the wire is given by:

where r is the radius of the wire. In this problem,
, so the cross-sectional area is

and the average current density is
