The presence of helium gas indicates the radioactive sample is most likely decaying by α-decay, or alpha decay. α-decay is the type of radioactive decay in which an atomic nucleus emits α particles. α particles are Helium nuclei. So the correct answer would be α-decay.
Answer:
The height of Sears Tower is 1448.5 feet.
Explanation:
<h3>
We apply the free fall formula to the ball:
</h3><h3>

</h3><h3>y: The vertical distance the ball moves at time t </h3><h3>

i: Initial speed
</h3><h3>g=Gravity acceleration=

</h3>
Known information
We know that the vertical distance (y) that the ball moves in 9,5s is equal to height of Sears Tower (h).
Too we know that the ball is released from rest, then,
=0
Height of Sears Tower calculation:
We replace in the equation 1 the data following;






Answer: The height of Sears Tower is 1448.5 ft
V = u + at
<span>= 0 + (9.81)(10) </span>
<span>= 98.1m/s </span>
<span>Ignoring air resistance.</span>