a)
• P = F/A
P = pressure = 630 N/m^2
F = force
A = area
F = mg = 0.50 kg x 9.8 m/s^2 = 4.9 N
m= mass
g= gravity
P = F/A
A = F/P
A = 4.9 N / 630 N/m^2 = 7.778 x 10^-3 m^2 
b)
• Area of a circle = pi* radius ^2
7.778 x 10^-3 m^2 = pi* radius ^2
√(7.778 x 10^-3 m^2 / pi ) = radius
radius = 0.04976 m 
Answers:
a ) 7.778 x 10^-3 m^2 
b) 0.04976 m 
 
        
             
        
        
        
K.E1=1/2×100×3²
 =50×9
 =450J
K.E2=1/2×100×36
 =50×36
 =1800J
        
                    
             
        
        
        
Answer:
I think it's bigger than most galaxies 
 
        
                    
             
        
        
        
Answer and explanation:
A.
Muon travelled straight down towards the earth. Therefore the tree moves up in the rest frame of muon (option a)
B.
In muon rest frame it travels Zero meters
C.
Distance, d = Velocity, v * Time, s


D.
Distance from the top of the mountain to the tree is the same as the distance travelled by the tree in the muons rest frame
that is same as in part C which is 594m
E.
Using lorentz contraction
In the rest frame of someone standing on the mountain 
the distance is given by




d' = 258.92m
F.
in the rest frame of someone standing on the mountain, 
muon moves straight down
 
        
             
        
        
        
Answer:
R=3818Km
Explanation:
Take a look at the picture. Point A is when you start the stopwatch. Then you stand, the planet rotates an angle α and you are standing at point B.
Since you travel 2π radians in 24H, the angle can be calculated as:
  t being expressed in hours.

From the triangle formed by A,B and the center of the planet, we know that:
  Solving for r, we get:
