Answer:
6 Ω
Explanation:
Two resistors in parallel = 3.75 ohm when one is 10 ...
r1 * r2 / (r1+r2) = 3.75
10 r2 / ( 10 + r2 )= 3.75
10 r2 = 37.5 + 3.75r2
6.25 r2 = 37.5
r2 = 6Ω
Ordinary cells can convert chemical energy to electrical energy only, but rechargeable cells can also store electrical energy into chemical energy and vice versa. You will study more about it in your higher classes. secondary cells can be recharged and used again but dry cells cannot be recharged.
Answer:

Explanation:
According to the law of conservation of energy, the total energy of the system can be expresed as the sum of the potential energy and kinetic energy:

When the spring is in its equilibrium position, that is
, the object speed its maximum. So, we have:

In order to double its maximum speed, that is
. We have:

No friction present means: Ek = Ep
So Ek = mgh = 10 * 9.8 * 2 = 196 J