Answer:
2.03 x 10²⁴N
Explanation:
Given parameters: 
Mass of moon = 7.34 x 10²²kg
Mass of the earth  = 5.97 x 10²⁴kg 
Distance  = 3.8 x 10⁵km
Unknown: 
Gravitational force of attraction  = ? 
Solution:
To find the gravitational force of attraction between the masses, we use the expression below;
    F =  
 
G is the universal gravitation constant
m is the mass 
1 and 2 represents moon and earth
r is  the distance
   F =  
 
  F =  = 2.03 x 10²⁴N
  = 2.03 x 10²⁴N
 
        
             
        
        
        
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 ans will be because it has 1.672
 
        
             
        
        
        
C. <span>People need time to shift between two different stimuli.</span>