Answer:
1373.4 N/m
Explanation:
Hooke's law states that the extension of a spring and force are related by the expression, F=kx where k is spring constant, x is extension of spring and F is the applied force. Making k the subject of the formula then 

Also, F=gm hence the above formula is modified as 

Taking g as 9.81 m/s2 , x as 0.5 m and m as 70 kg then

 
        
             
        
        
        
Answer:
a). V = 3.13*10⁶ m/s
b). T = 1.19*10^-7s
c). K.E = 2.04*10⁵
d). V = 1.02*10⁵V
Explanation:
q = +2e
M = 4.0u 
r = 5.94cm = 0.0594m
B = 1.10T
1u = 1.67 * 10^-27kg
M = 4.0 * 1.67*10^-27 = 6.68*10^-27kg
a). Centripetal force = magnetic force
Mv / r = qB
V = qBr / m
V = [(2 * 1.60*10^-19) * 1.10 * 0.0594] / 6.68*10^-27
V = 2.09088 * 10^-20 / 6.68 * 10^-27
V = 3.13*10⁶ m/s
b). Period of revolution.
T = 2Πr / v 
T = (2*π*0.0594) / 3.13*10⁶ 
T = 1.19*10⁻⁷s
c). kinetic energy = ½mv²
K.E = ½ * 6.68*10^-27 * (3.13*10⁶)²
K.E = 3.27*10^-14J
1ev = 1.60*10^-19J
xeV = 3.27*10^-14J
X = 2.04*10⁵eV
K.E = 2.04*10⁵eV
d). K.E = qV 
V = K / q
V = 2.04*10⁵ / (2eV).....2e-
V = 1.02*10⁵V
 
        
             
        
        
        
Answer:
The value is  
Explanation:
From the question we are told that 
      The mass of the car is   
 
       The period of the circular motion is  
       The radius  is 
Generally the frequency of the circular motion is  
        
=>    
=>    
 
        
             
        
        
        
<h2>
Answer: The half-life of beryllium-15 is 400 times greater than the half-life of beryllium-13.</h2>
Explanation:
The half-life  of a radioactive isotope refers to its decay period, which is the average lifetime of an atom before it disintegrates.
 of a radioactive isotope refers to its decay period, which is the average lifetime of an atom before it disintegrates.
In this case, we are given the half life of two elements:
beryllium-13: 
beryllium-15: 
As we can see, the half-life of beryllium-15  is greater than the half-life of beryllium-13, but how great?
We can find it out by the following expression:

Where  is the amount we want to find:
 is the amount we want to find:


Finally:

Therefore:
The half-life of beryllium-15 is <u>400 times greater than</u> the half-life of beryllium-13.
 
        
        
        
Explanation:
Given parameters: 
Mass of Neil Armstrong = 160kg
Gravitational pull of earth = 10N/kg
Moon's pull = 17% of the earth's pull
Unknown: 
Difference between Armstrong's weight on moon and on earth. 
Solution: 
To find the weight, 
    Weight = mass x acceleration due to gravity = mg
Moon's gravitational pull = 17% of the earth's pull = 17% x 10 = 1.7N/kg
Weight on moon = 160 x 1.7 = 272N
Weight on earth = 160 x 10 = 1600N
The difference in weight = 1600 - 272 = 1328N
The weight of Armstrong on earth is 1328N more than on the moon.
Learn more: 
Weight and mass brainly.com/question/5956881
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