a una velocidad de
22 m/s, quien lo golpea y devuelve en la misma
dirección con una velocidad de 14 m/s. Si el
tiempo de contacto del balón con la jugadora es
de 0,03 s, ¿con qué fuerza golpeó la jugadora el
balón?
21 Una bala de 0,8 g, está en la recámara de un rifl e
cuando se g
Answer:

Explanation:
The power provided by a resistor (wire in this case) is given by:
.
The resistance of a wire is given by:

Where for the resistivity the one of the copper should be used:
.
The area A is that of a circle, which written in terms of its diameter is:

Putting all together:

Which for our values is:

Imagine an object is moving in one dimension on a number line, and for this we'll say that the numbers on the line are a metre apart. If the object moves from 2 m to 7 m, the change in position is 7-2=+5 metres. But if the object moves back from 7 m to 2 m, the change in position is 2-7=-5 metres. since

, and time is always positive, velocity will be positive in one direction and negative in the other direction.
Answer:
B. decreases while his angular speed remains unchanged.
Explanation:
His angular speed will always be the same as the wheel's angular speed, which remains constant as it's in uniform motion. As for linear speed, which is defined as the product of angular speed and distance r to the center of rotation, and his distance to center is decreasing, his linear speed must be decreasing as well.
Answer:
Rhythmic Gymnastics
Explanation:
In general, the judges in the sports tend to be in charge for correcting and controlling the breaking of the rules in the particular sport. They are allowed to punish the competitors in accordance with the breaking of the rule, or they are there in order to determine weather a point is regular or not. In the rhythmic gymnastics though, and sports similar to it, the judges have different role, as they are in charge of determining the points earned by the competitors. This is done in a manner where every judge gives certain amount of points, or grades, and when those are summed up, the competitors get their total points.