Hello there!
Essentially, a control variable is what is kept the same throughout the experiment, and it is not of primary concern in the experimental outcome. Any change in a control variable in an experiment would invalidate the correlation of dependent variables (DV) to the independent variable (IV), thus skewing the results.
Answer:
emf will also be 10 times less as compared to when it has fallen 
Explanation:
We know, from faraday's law-

and 
So, as the height increases the velocity with which it will cross the ring will also increase. 
Given


Now, from 

From equation a and b we see that velocity when dropped from
is 10 times greater when height is 40
so, emf will also be 10 times less as compared to when it has fallen 
Answer:
La posición en la que se encuentra el móvil en el instante t = 30 s es 172 m.
Explanation:
El movimiento rectilíneo uniforme (MRU) es el movimiento que describe un cuerpo o partícula a través de una línea recta a velocidad constante.
La distancia recorrida, x
, por un móvil que tiene un MRU con un velocidad v durante el intervalo de tiempo t es:
x= x0 + v*t
donde x0 es la posición inicial.
En este caso:
Reemplazando:
x= 22 m + 5 m/s* 30 s
Resolviendo:
x= 22 m + 150 m
x= 172 m
<u><em>La posición en la que se encuentra el móvil en el instante t = 30 s es 172 m.</em></u>
The weight of the object on mars is about 80n