2) Curium-242 experiences alpha decay 3) Ruthenium-106 undergoes beta decay
4) Uranium-234 undergoes alpha decay
5) Cesium-137 emits a beta particle
6) The half life of lead-210 is 30.4 years. If Z4g sample of lead-210 sits for 91.2 years, what is the final mass?

answer;

18.5 seconds

explanation;

velocity is distance covered per unit time; it is given by displacement divided by time.

thus; time = displacement/velocity

total time = total displacement/velocity

total distance = 5000 meters south

total time = 5000/4.5

                  = 1111.11 seconds

but; 1 minute = 60 sec

thus; 1111.11 /60

                = 18.51 seconds

thus; the time taken is 18.5 seconds