Grade 11Mechanics

n identical cubes each of mass m and edge L are on a floor .if the cubes are to be arranged one over the other in a vertical stack ,the work to be done is

sadvik reddy

8 Years agoGrade 11

2 Answers

Arun

8 Years ago

Work done in placing a 2nd cube on the first one, W2 mgl
Similarly W3 = 2 mgl
W4 = 3 mgl
Wn = (n -1) mgl
Total work done WN = W1+ W2+ W3...+Wn
WN = [ mgl+2mgl+3mgl....(n - 1) mgl ]
WN =mgl [ 1+2+3+......(n - 1) ]

Chintan Shah

7 Years ago

Work done in placing first cube is 0.

Work done in placing 2nd cube is mgl.

Similarly, W3=2mgl,.....,Wn=(n-1)mgl.

Wnet= W1+W2+W3+......+W(n-1)

= mgl{1+2+3+....+(n-1)}

= mgl{Sn}

= mgl{(n-1)/2 [2×1+(n-1-1)1]}

= mgl{(n-1)/2×n}

Wnet = mgln(n-1)/2.

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n identical cubes each of mass m and edge L are on a floor .if the cubes are to be arranged one over the other in a vertical stack ,the work to be done is

sadvik reddy

2 Answers

Arun

Chintan Shah

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