Answer:
Protons = 50
Mass number = 119
Explanation:
A neutral of tin, Sn, has a Z value of 50 and neutrons are 69.
Z is the atomic number. The atomic number is equal to number of protons or number of electrons in an atom that is neutral i.e:
 Z = PROTONS = ELECTRONS
So the number of protons = 50 since Z is 50
>>>>>>>>>>>>>>>¦
The bulk of the mass of an atom is concentrated in the nucleus. To calculate mass number, we simply sum all the elementary particles in the nucleus i.e protons and neutrons. These particles are called the nucleons. 
Mass number (A) = P + N
 = 50 + 69
 = 119
 
        
             
        
        
        
Answer:
9 m 
Explanation:
i did the test and got 100%
 
        
             
        
        
        
Answer:
m = 3 kg
The mass m is 3 kg
Explanation:
From the equations of motion;
s = 0.5(u+v)t
Making t thr subject of formula;
t = 2s/(u+v)
t = time taken
s = distance travelled during deceleration = 62.5 m
u = initial speed = 25 m/s
v = final velocity = 0
Substituting the given values;
t = (2×62.5)/(25+0) 
t = 5
Since, t = 5 the acceleration during this period is;
acceleration a = ∆v/t = (v-u)/t
a = (25)/5 
a = 5 m/s^2
Force F = mass × acceleration
F = ma
Making m the subject of formula;
m = F/a
net force F = 15.0N
Substituting the values
m = 15/5
m = 3 kg
The mass m is 3 kg