The ball was moving for 0.8seconds
This is because 4/5 x 1 = 0.8
Hope this helps and good luckkkk :)
The intensity of the magnetic force F experienced by a charge q moving with speed v in a magnetic field of intensity B is equal to

where

is the angle between the directions of v and B.
1) Re-arranging the previous formula, we can calculate the value of the magnetic field intensity. The charge is

. In this case, v and B are perpendicular, so

, therefore we have:

2) In this second case, the angle between v and B is

. The charge is now

, and the magnetic field is the one we found in the previous part, B=2.8 T, so we can find the intensity of the force experienced by this second charge:
Answer:
C.<u>ten</u><u> </u><u>times</u><u> </u><u>the</u><u> </u><u>intensity</u><u>.</u>
Answer: in the smaller/ thinner pieces.