The time for half the atoms in a radioactive substance to disintegrate
https://www.vocabulary.com/dictionary/half-life
Answer:
The thrown rock strike 2.42 seconds earlier.
Explanation:
This is an uniformly accelerated motion problem, so in order to find the arrival time we will use the following formula:

So now we have an equation and unkown value.
for the thrown rock

for the dropped rock

solving both equation with the quadratic formula:

we have:
the thrown rock arrives on t=5.4 sec
the dropped rock arrives on t=7.82 sec
so the thrown rock arrives 2.42 seconds earlier (7.82-5.4=2.42)
I believe it is called an ampere.
The linear velocity of a rotating object is the product of the angular velocity and the radius of the circular motion. Angular velocity is the rate of the change of angular displacement of a body that is in a circular motion. It is a vector quantity so it consists of a magnitude and direction. From the problem, the angular velocity is 5.9 rad per second and the radius is given as 12 centimeters. We calculate as follows:
Linear velocity = angular velocity (radius)
Linear velocity = 5.9 (12 ) = 70.8 cm / s
The linear velocity of the body in motion is 70.8 centimeters per second or 0.708 meters per second.
Magnitude of displacement = 
Adding the squares gives displacement = 
Displacement =
≈ 724.7m