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Work, Energy and Power

268757 ' $n$ ' 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

1 Lmng (n-1)/2

2

Lg (n - 1) / m n

3 (n-1)/Lmng

4

Lmng / 2 (n - 1)

Explanation:

$U_{i} = n m g ◻ \frac{L}{2} ⊟, U_{f} = n m g ◻ \frac{n L}{2} ⊟, W = U_{i} - U_{f}$

Work, Energy and Power

268758 A chain of mass $m$ and length ' $L$ ' is over hanging from the edge of a smooth horizontal table such that $3 / 4$ th of its length is lying on the table. The work done in pulling the chain completely on to the table is

1

mgL / 16

2

mgL / 32

3

3 mgL / 32

4

mgL / 8

Explanation:

$W = \frac{m g l}{2 n^{2}}$

Work, Energy and Power

268820 A weight of $5 N$ is moved up a frictionless inclined plane from $R$ to $Q$ as shown.

What is the work done in joules?

1 15

2 20

3 25

4 35

Explanation:

$W = mgh$

Work, Energy and Power

268821 A $5 kg$ stone of relative density 3 is resting at the bed of a lake. It is raised through a height of $5 m$ in the lake. If $g = 10 m / s^{2}$ , then work done is

1

\frac{500}{3} J

2

\frac{350}{3} J

3

\frac{750}{3} J

4

\frac{550}{3} J

Explanation:

$w = m g h ◻^{◻} - \frac{d_{L}}{d_{B}} ◻$

Work, Energy and Power

268757 ' $n$ ' 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

1 Lmng (n-1)/2

2

Lg (n - 1) / m n

3 (n-1)/Lmng

4

Lmng / 2 (n - 1)

Explanation:

$U_{i} = n m g ◻ \frac{L}{2} ⊟, U_{f} = n m g ◻ \frac{n L}{2} ⊟, W = U_{i} - U_{f}$

Work, Energy and Power

268758 A chain of mass $m$ and length ' $L$ ' is over hanging from the edge of a smooth horizontal table such that $3 / 4$ th of its length is lying on the table. The work done in pulling the chain completely on to the table is

1

mgL / 16

2

mgL / 32

3

3 mgL / 32

4

mgL / 8

Explanation:

$W = \frac{m g l}{2 n^{2}}$

Work, Energy and Power

268820 A weight of $5 N$ is moved up a frictionless inclined plane from $R$ to $Q$ as shown.

What is the work done in joules?

1 15

2 20

3 25

4 35

Explanation:

$W = mgh$

Work, Energy and Power

268821 A $5 kg$ stone of relative density 3 is resting at the bed of a lake. It is raised through a height of $5 m$ in the lake. If $g = 10 m / s^{2}$ , then work done is

1

\frac{500}{3} J

2

\frac{350}{3} J

3

\frac{750}{3} J

4

\frac{550}{3} J

Explanation:

$w = m g h ◻^{◻} - \frac{d_{L}}{d_{B}} ◻$

Work, Energy and Power

268757 ' $n$ ' 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

1 Lmng (n-1)/2

2

Lg (n - 1) / m n

3 (n-1)/Lmng

4

Lmng / 2 (n - 1)

Explanation:

$U_{i} = n m g ◻ \frac{L}{2} ⊟, U_{f} = n m g ◻ \frac{n L}{2} ⊟, W = U_{i} - U_{f}$

Work, Energy and Power

268758 A chain of mass $m$ and length ' $L$ ' is over hanging from the edge of a smooth horizontal table such that $3 / 4$ th of its length is lying on the table. The work done in pulling the chain completely on to the table is

1

mgL / 16

2

mgL / 32

3

3 mgL / 32

4

mgL / 8

Explanation:

$W = \frac{m g l}{2 n^{2}}$

Work, Energy and Power

268820 A weight of $5 N$ is moved up a frictionless inclined plane from $R$ to $Q$ as shown.

What is the work done in joules?

1 15

2 20

3 25

4 35

Explanation:

$W = mgh$

Work, Energy and Power

268821 A $5 kg$ stone of relative density 3 is resting at the bed of a lake. It is raised through a height of $5 m$ in the lake. If $g = 10 m / s^{2}$ , then work done is

1

\frac{500}{3} J

2

\frac{350}{3} J

3

\frac{750}{3} J

4

\frac{550}{3} J

Explanation:

$w = m g h ◻^{◻} - \frac{d_{L}}{d_{B}} ◻$

Work, Energy and Power

268757 ' $n$ ' 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

1 Lmng (n-1)/2

2

Lg (n - 1) / m n

3 (n-1)/Lmng

4

Lmng / 2 (n - 1)

Explanation:

$U_{i} = n m g ◻ \frac{L}{2} ⊟, U_{f} = n m g ◻ \frac{n L}{2} ⊟, W = U_{i} - U_{f}$

Work, Energy and Power

268758 A chain of mass $m$ and length ' $L$ ' is over hanging from the edge of a smooth horizontal table such that $3 / 4$ th of its length is lying on the table. The work done in pulling the chain completely on to the table is

1

mgL / 16

2

mgL / 32

3

3 mgL / 32

4

mgL / 8

Explanation:

$W = \frac{m g l}{2 n^{2}}$

Work, Energy and Power

268820 A weight of $5 N$ is moved up a frictionless inclined plane from $R$ to $Q$ as shown.

What is the work done in joules?

1 15

2 20

3 25

4 35

Explanation:

$W = mgh$

Work, Energy and Power

268821 A $5 kg$ stone of relative density 3 is resting at the bed of a lake. It is raised through a height of $5 m$ in the lake. If $g = 10 m / s^{2}$ , then work done is

1

\frac{500}{3} J

2

\frac{350}{3} J

3

\frac{750}{3} J

4

\frac{550}{3} J

Explanation:

$w = m g h ◻^{◻} - \frac{d_{L}}{d_{B}} ◻$