QBManager

Work, Energy and Power

268653 A tank of size $10 m \times 10 m \times 10 m$ is full of water and built on the ground. If $g = 10 {ms}^{- 2}$ , the potential energy of the water in the tank is

1

5 \times 10^{7} J

2

1 \times 10^{8} J

3

5 \times 10^{4} J

4

5 \times 10^{5} J

Explanation:

P.E $= {mgh}_{1}$ ; here $h_{1} = \frac{h}{2}$ and $m = ρ \times V$

Work, Energy and Power

268654 A bolt of mass $0.3 kg$ falls from the ceiling of an elevator moving down with an uniform speed of $7 m / s$ . It hits the floor of the elevator (length of the elevator $= 3 m$ ) and does not rebound. What is the heat produced by impact?

1 8.82J

2

7.72 J

3

6.62 J

4

5.52 J

Explanation:

Heat produced $=$ loss of potential energy $= mgh$

Work, Energy and Power

268655 A spring when compressed by $4 cm$ has $2 J$ energy stored in it. The force required to extend it by $8 cm$ will be

1

20 N

2

2 N

3

200 N

4

2000 N

Explanation:

$U = \frac{1}{2} K x_{1}^{2} \Rightarrow K = \frac{2 U}{x_{1}^{2}}$ and $F = K x_{2}$

Work, Energy and Power

268656 The elastic potential energy of a stretched spring is given by $E = 50 x^{2}$ . Where $x$ is the displacement in meter and $E$ is in joule, then the force constant of the spring is

1

50 Nm

2

100 N m^{- 1}

3

100 N / m^{2}

4

100 Nm

Explanation:

$U = \frac{1}{2} K x^{2} - - (1), U = 50 x^{2} - - (2),$ compare equation (1) and (2) to find $K$

Work, Energy and Power

268653 A tank of size $10 m \times 10 m \times 10 m$ is full of water and built on the ground. If $g = 10 {ms}^{- 2}$ , the potential energy of the water in the tank is

1

5 \times 10^{7} J

2

1 \times 10^{8} J

3

5 \times 10^{4} J

4

5 \times 10^{5} J

Explanation:

P.E $= {mgh}_{1}$ ; here $h_{1} = \frac{h}{2}$ and $m = ρ \times V$

Work, Energy and Power

268654 A bolt of mass $0.3 kg$ falls from the ceiling of an elevator moving down with an uniform speed of $7 m / s$ . It hits the floor of the elevator (length of the elevator $= 3 m$ ) and does not rebound. What is the heat produced by impact?

1 8.82J

2

7.72 J

3

6.62 J

4

5.52 J

Explanation:

Heat produced $=$ loss of potential energy $= mgh$

Work, Energy and Power

268655 A spring when compressed by $4 cm$ has $2 J$ energy stored in it. The force required to extend it by $8 cm$ will be

1

20 N

2

2 N

3

200 N

4

2000 N

Explanation:

$U = \frac{1}{2} K x_{1}^{2} \Rightarrow K = \frac{2 U}{x_{1}^{2}}$ and $F = K x_{2}$

Work, Energy and Power

268656 The elastic potential energy of a stretched spring is given by $E = 50 x^{2}$ . Where $x$ is the displacement in meter and $E$ is in joule, then the force constant of the spring is

1

50 Nm

2

100 N m^{- 1}

3

100 N / m^{2}

4

100 Nm

Explanation:

$U = \frac{1}{2} K x^{2} - - (1), U = 50 x^{2} - - (2),$ compare equation (1) and (2) to find $K$

Work, Energy and Power

268653 A tank of size $10 m \times 10 m \times 10 m$ is full of water and built on the ground. If $g = 10 {ms}^{- 2}$ , the potential energy of the water in the tank is

1

5 \times 10^{7} J

2

1 \times 10^{8} J

3

5 \times 10^{4} J

4

5 \times 10^{5} J

Explanation:

P.E $= {mgh}_{1}$ ; here $h_{1} = \frac{h}{2}$ and $m = ρ \times V$

Work, Energy and Power

268654 A bolt of mass $0.3 kg$ falls from the ceiling of an elevator moving down with an uniform speed of $7 m / s$ . It hits the floor of the elevator (length of the elevator $= 3 m$ ) and does not rebound. What is the heat produced by impact?

1 8.82J

2

7.72 J

3

6.62 J

4

5.52 J

Explanation:

Heat produced $=$ loss of potential energy $= mgh$

Work, Energy and Power

268655 A spring when compressed by $4 cm$ has $2 J$ energy stored in it. The force required to extend it by $8 cm$ will be

1

20 N

2

2 N

3

200 N

4

2000 N

Explanation:

$U = \frac{1}{2} K x_{1}^{2} \Rightarrow K = \frac{2 U}{x_{1}^{2}}$ and $F = K x_{2}$

Work, Energy and Power

268656 The elastic potential energy of a stretched spring is given by $E = 50 x^{2}$ . Where $x$ is the displacement in meter and $E$ is in joule, then the force constant of the spring is

1

50 Nm

2

100 N m^{- 1}

3

100 N / m^{2}

4

100 Nm

Explanation:

$U = \frac{1}{2} K x^{2} - - (1), U = 50 x^{2} - - (2),$ compare equation (1) and (2) to find $K$

Work, Energy and Power

268653 A tank of size $10 m \times 10 m \times 10 m$ is full of water and built on the ground. If $g = 10 {ms}^{- 2}$ , the potential energy of the water in the tank is

1

5 \times 10^{7} J

2

1 \times 10^{8} J

3

5 \times 10^{4} J

4

5 \times 10^{5} J

Explanation:

P.E $= {mgh}_{1}$ ; here $h_{1} = \frac{h}{2}$ and $m = ρ \times V$

Work, Energy and Power

268654 A bolt of mass $0.3 kg$ falls from the ceiling of an elevator moving down with an uniform speed of $7 m / s$ . It hits the floor of the elevator (length of the elevator $= 3 m$ ) and does not rebound. What is the heat produced by impact?

1 8.82J

2

7.72 J

3

6.62 J

4

5.52 J

Explanation:

Heat produced $=$ loss of potential energy $= mgh$

Work, Energy and Power

268655 A spring when compressed by $4 cm$ has $2 J$ energy stored in it. The force required to extend it by $8 cm$ will be

1

20 N

2

2 N

3

200 N

4

2000 N

Explanation:

$U = \frac{1}{2} K x_{1}^{2} \Rightarrow K = \frac{2 U}{x_{1}^{2}}$ and $F = K x_{2}$

Work, Energy and Power

268656 The elastic potential energy of a stretched spring is given by $E = 50 x^{2}$ . Where $x$ is the displacement in meter and $E$ is in joule, then the force constant of the spring is

1

50 Nm

2

100 N m^{- 1}

3

100 N / m^{2}

4

100 Nm

Explanation:

$U = \frac{1}{2} K x^{2} - - (1), U = 50 x^{2} - - (2),$ compare equation (1) and (2) to find $K$