The practice of playing top hits several times a day on radio stations is called rotation.
Answer:
120 mA
Explanation:
The relationship between voltage, current and resistance in a circuit is given by Ohm's law

where
I is the current
V is the voltage
R is the resistance
In this problem, we have an initial current of
I = 60 mA
Then the voltage is doubled:
V' = 2 V
while the resistance is kept the same:
R' = R
So the new current is

so, the current has doubled. Since I = 60 mA, the new current is

m = mass of the roller coaster = 500 kg
h = height of the hill = 80 m
v = speed of the roller coaster at the bottom of the hill = ?
using conservation of energy
kinetic energy at the bottom of the hill = potential energy at the top of hill
(0.5) m v² = m g h
(0.5) v² = g h
inserting the values
(0.5) v² = (9.8) (80)
v = 39.6 m/s
hence the speed at the bottom comes out to be 39.6 m/s