Respuesta :
Answer:
Work done is 1.920 kJ
Solution:
As per the question:
The original weight of the sand = 134 lb
The final weight of the sand after the leakage of 12 lb of the sand from it = 134 - 12 = 122 lb
The height to which it was raised, h = 15 ft
Now,
The work done can be calculated as:
Average weight of the sand, [tex]w_{a} = \frac{(134 + 122)}{2} = 128 lb[/tex]
Work done = [tex]w_{a}\times h = 128\times 15 = 1920 J = 1.920 kJ[/tex]
Answer:1920 lb-ft
Explanation:
Given
Weight of cement bag=134 lb
Cement leaked=12 lb
height =15 ft
Let Weight be a linear function of distance moved such that
w=-ax+b
at x=0 ,w=134 lb
at x=15, w=134-12=122 lb
Thus b=134 ,a=0.8
and work done is
[tex]W=\int_{0}^{15}wdx[/tex]
[tex]W=\int_{0}^{15}\left ( -0.8x+134\right )dx[/tex]
[tex]W=\left ( -0.4\times x^2+134x\right )_0^15[/tex]
[tex]W=-0.4\times 225+134\times 15[/tex]
W=1920 lb-ft
