Answer:
W = 311074.5 [J]
Explanation:
In order to solve this problem we must analyze two parts, in the first part by means of Newton's second law we can determine the acceleration of the beam, remembering that the sum of the forces is equal to the product of mass by acceleration.
∑F = m*a
F = forces acting on the beam [N]
m = mass = 425 [kg]
a = acceleration = 1.8 [m/s²]
The forces acting on the beam are the force of the crane up (positive) and the weight of the beam down (negative)
![F_{crane}-(425*9.81)= 425*1.8\\F_{crane}=4713.25 [N]](https://tex.z-dn.net/?f=F_%7Bcrane%7D-%28425%2A9.81%29%3D%20425%2A1.8%5C%5CF_%7Bcrane%7D%3D4713.25%20%5BN%5D)
Now in the second part, we use the definition of work, which is equal to the product of the force applied in the direction of displacement, that is, the product of force by distance.

where:
W = work [J]
F = force = 4713.25 [N]
d = distance = 66 [m]
![W=4713.25*66\\W=311074.5[J]](https://tex.z-dn.net/?f=W%3D4713.25%2A66%5C%5CW%3D311074.5%5BJ%5D)
 
        
             
        
        
        
Answer:
1920Joules
Explanation:
The formula for calculating the kinetic energy of a body is expressed as;
KE = 1/2 mv²
m isthe mass
V is the speed
For the two masses, the combined KE is expressed as;
KE  = 1/2(m1+m2)v²
KE = 1/2(45+15)(8)²
KE  = 1/2 * 60 * 64
KE  = 30 * 64
KE  = 1920J
Hence the combined kinetic energy of the boy and the bicycle is 1920Joules
 
        
             
        
        
        
Answer:
a = -2.4 m/s²
Explanation:
Given,
The initial speed of the bus, u = 24 m/s
The final speed of bus, v = 12 m/s
Time taken to reach final speed is, t = 5.0 s
The acceleration of the body is given by the change in velocity by time
                                       a = (v - u) / t
                                          = (12 - 24) / 5
                                          = -2.4 m/s²
The negative sign in the acceleration indicates that the bus is decelerating.
Therefore, the acceleration of the bus is, a = -2.4 m/s²
 
        
             
        
        
        
Answer:

Explanation:
From the question we are told that:
Length 
Mass 
Distance from Tip 
Generally, the equation for Torque Balance is mathematically given by


Therefore

 
        
             
        
        
        
Answer:
What material structure explanation lies behind the fact that the propagation velocity of longitudinal waves is the lowest in gases and the highest in solids?