Explanation:
Given that,
The slope of the ramp, 
Mass of the box, m = 60 kg
(a) Distance covered by the truck up the slope, d = 300 m
Initially the truck moves with a constant velocity. We know that the net work done on the box is equal to 0 as per work energy theorem as :

u and v are the initial and the final velocity of the truck 
(b) The work done on the box by the force of gravity is given by :

Here, 


W = -24550.13 J
(c) What is the work done on the box by the normal force is equal to 0 as the angle between the force and the displacement is 90 degrees.
(d) The work done by friction is given by :


Hence, this is the required solution.
 
        
             
        
        
        
<u>Answers</u>
(a)  6.75 Joules.
(b)  5.27 m/s
(c) 0.75 Joules
<u>Explanation</u>
Kinetic energy is the energy possessed by a body in motion.
(a) its kinetic energy at A?
K.E = 1/2 mv²
        = 1/2 ×  0.54 × 5²
        = 6.75 Joules.
(b) its speed at point B?
K.E = 1/2 mv²
7.5 = 1/2 × 0.54 × V²
V² = 7.5 ÷ 0.27
      = 27.77778 
V = √27.77778
    = 5.27 m/s
(c) the total work done on the particle as it moves from A to B?
 Work done = 7.5 - 6.75 
                  = 0.75 Joules
 
        
             
        
        
        
Answer:
The equation which define the work done by spring is w = 45 x³ - 8 x² 
Explanation:
Given as :
The force is the function of distance x
I.e F(x) = a x² - b x
where 
a = 45 N/m²
b = 8 N/m
Now, Wok done = Force ×displacement
I.e W = F . ds
So , W = (a x² - b x) × x
or, W = (45 x² - 8 x) × x
Or, w = 45 x³ - 8 x² 
So, the equation which define the work done by spring is w = 45 x³ - 8 x² 
Hence The equation which define the work done by spring is w = 45 x³ - 8 x²  Answer
 
        
             
        
        
        
 A wave front has the form of a surface of a sphere