Answer:
Explanation:
this is the answer to your question
Answer:
The deceleration is 4 times higher for 0.5sec than for 2 sec.
Explanation:
If the deceleration happens from 1800deg/sec to zero in 2 sec we have that the magnitude is:

if now the time to decelerate is 0.5sec:

The deceleration is now 4 times higher than the previous situation.
The mass of a radioactive element at time t is given by

where

is the mass at time zero, while

is the half-life of the element.
In our problem,

, t=121.0 s and

, so we can find the initial mass

: