Answer: a) 3.85 days
b) 10.54 days
Explanation:-
Expression for rate law for first order kinetics is given by:

where,
k = rate constant = ?
t = time taken for decomposition = 3 days
a = let initial amount of the reactant = 100 g
a - x = amount left after decay process = 
First we have to calculate the rate constant, we use the formula :
Now put all the given values in above equation, we get


a) Half-life of radon-222:


Thus half-life of radon-222 is 3.85 days.
b) Time taken for the sample to decay to 15% of its original amount:
where,
k = rate constant = 
t = time taken for decomposition = ?
a = let initial amount of the reactant = 100 g
a - x = amount left after decay process = 


Thus it will take 10.54 days for the sample to decay to 15% of its original amount.
Answer:
The net force is the vector sum of all the forces that act upon an object. That is to say, the net force is the sum of all the forces, taking into account the fact that a force is a vector and two forces of equal magnitude and opposite direction will cancel each other out.
Explanation:
put in your own words PLEASE, hope it helps
55 meters. If she started at 10 meters and ran 45 more, 10+45=55.
Answer:
the tension is 18513N
Explanation:
Given that
mass = 1683kg
acceleration = 1.2m/s^2
acceleration due to gravity = 9.8m/s^2
T-mg = ma
T = ma + mg
T = m(a +g)
T = 1683 kg(1.20 m/s2 + 9.8)
T = 1683 (11)
T = 18513N
therefore, the tension is 18513N