Answer:
a= - 6.667 m/s² 
Explanation:
Given that
The initial speed of the box ,u= 20 m/s
The final speed of the box ,v=  0 m/s
The distance cover by box ,s= 30 m
Lets take the acceleration of the box = a 
We know that
v²= u ² + 2 a s
Now by putting the values in the above equation we get
0²=20² + 2 a x 30 

a= - 6.667 m/s² 
Negative sign indicates that velocity and acceleration are in opposite direction.
Therefore the acceleration of the box will be  - 6.667 m/s² .
 
        
             
        
        
        
Answer:
Index of expansion: 4.93
Δu = -340.8 kJ/kg
q = 232.2 kJ/kg
Explanation:
The index of expansion is the relationship of pressures:
pi/pf
The ideal gas equation:
p1*v1/T1 = p2*v2/T2
p2 = p1*v1*T2/(T2*v2)
500 C = 773 K
20 C = 293 K
p2 = 35*0.1*773/(293*1.3) = 7.1 bar
The index of expansion then is 35/7.1 = 4.93
The variation of specific internal energy is:
Δu = Cv * Δt
Δu = 0.71 * (20 - 500) = -340.8 kJ/kg
The first law of thermodynamics
q = l + Δu
The work will be the expansion work
l = p2*v2 - p1*v1
35 bar = 3500000 Pa
7.1 bar = 710000 Pa
q = p2*v2 - p1*v1 + Δu
q = 710000*1.3 - 3500000*0.1 - 340800 = 232200 J/kg = 232.2 kJ/kg
 
        
             
        
        
        
Answer:
Option C
Explanation:
v= u + at
20 = 5 + a(5)
15= a(5)
a= 3 m/s²
Force = mass × acceleration
= 10 × 3
= 30 N
 
        
             
        
        
        
Answer:
The minimum wall thickness required for the spherical tank is 0.0189 m
Explanation:
Given data:
d = inside diameter = 8.1 m
P = internal pressure = 1.26 MPa
σ = 270 MPa
factor of safety = 2
Question: Determine the minimum wall thickness required for the spherical tank, tmin = ?
The allow factor of safety:

The minimun wall thickness:

 
        
             
        
        
        
Hello!
Recall the equation for gravitational force:

Fg = Force of gravity (N)
G = Gravitational constant 
m1, m2 = masses of objects (kg)
r = distance between the objects' center of masses (m)
There is a DIRECT relationship between mass and gravitational force. 
We are given:

If we were to double one mass and triple another, according to the equation:

Thus:
