if the half life of uranium 232 is 70 years how many half lives will it take for 10 grams of it to be reduced to 1.25 grams

Given :

The half life of uranium 232 is 70 years.

To Find :

How many half lives will it take for 10 grams of it to be reduced to 1.25 grams.

Solution :

We know, formula of radioactive decay is :

Here, is initial amount and N is remaining amount.

Putting all given values in above equation, we get :

Therefore, it takes 3 half lives i.e. 210 years to reduced to 1.25 grams.

explanation:

as the height from which the ruler was dropped increased, the speed of the ruler at ryan's hand increased.

force is mass*acceleration.

we have a very small mass: 11.4*0.001 kg

if we want 0.035n of force, we need an acceleration:

0.035 = 11.4*0.001*a

a = 0.035/(11.4*0.001) m/s^2