I do not know if it is correct but I think it is between B or C
The final velocity is 0 and the acceleration is gravity. Vf=Vi+at because gravity opposes the motion it will be -g
0=250-gt
gt=250 ....g=10
t=25sec
Answer:

Explanation:
From the question we are told that:
Time 
Generally the Period is given as

Therefore difference in frequency dF



12 is correct
Explanation: it's a cube
Answer:
The pair of terminals to produce an output voltage of 8V are K and M.
Explanation:
A transformer is an electronic device that can be used to increase or decrease an output voltage. It consists of secondary and primary coils, and operates on the principle of induction.
= 
where:
is the voltage in the secondary coil,
is the voltage in the primary coil,
is the number of turns in the secondary coil and
is the number of turns in the primary coil.
In the question, let us combine the number of turns in the secondary coil. So that,
= 15 + 5 = 20
= 
= 
= 8
= 8V
For the output voltage to be equal to 8V, the pair of terminals required are K and M.