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.
Take the stone's position at ground level to be the origin, and the downward direction to be negative. Then its position in the air 
at time 
is given by
Let 
be the depth of the well. The stone hits the bottom of the well after 5.00 s, so that
Answer:
Yes
Explanation:
The core of an electromagnet serves to stabilize the magnetic field created by the wire. The thicker the core, the more metal there is to amplify the current. Therefore, a thicker core does make an electromagnet stronger. Hope this helps!
