Answer:
Question one is b, Question two is b, and question three is b, im pretty positive that what it is
The sum of all resistances in the series circuit is known as Equivalent resistance.

where R is the equivalent resistance.
Hence, option 1 is the correct answer.
Answer: here you go i have to put 20 letters in so just ignore this and look at the link.
Answer:
a) y = 16.51 [m]
b) t = 1.83 [s]
Explanation:
To solve this problem we must use two kinematics equations, the first to determine the height to which the ball reaches, and the second equation to determine how long it lasts in the air.

where:
Vf = final velocity = 0
Vi = initial velocity = 18 [m/s]
g = gravity acceleration = 9.81[m/s^2]
t = time [s]
Note: the negative sign of the Equation indicates that the acceleration of gravity acts in the opposite direction to the movement of the ball. The final velocity is zero, since the ball reaches its maximum altitude when the velocity is zero.
Now replacing:
0 = (18)^2 - (2*9.81*y)
y = 16.51 [m]
b)

0 = 18 - (9.81*t)
t = 1.83 [s]
Name: Lead
Symbol: Pb
Atomic Number: 82
Atomic Mass: 207.2 amu
Melting Point: 327.5 °C (600.65 K, 621.5 °F)
Boiling Point: 1740.0 °C (2013.15 K, 3164.0 °F)
Number of Protons/Electrons: 82
Number of Neutrons: 125
Classification: Other Metals
Crystal Structure: Cubic
Density @ 293 K: 11.34 g/cm3
Color: bluish