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A 50-kg sack is lifted a vertical distance of 2 m another 25-kg sack is lifted a vertical distance of 4 m. If both sacks are lifted their respective distances in the same time, how does the power required for each compare? How about for the case in which the lighter sack is moved the same distance in half the time?

Respuesta :

Answer:

Part a)

Here in both cases we will have same power

Part b)

Again we have same power in above two cases

Explanation:

Part a)

As we know that power is defined as the work done per unit time

now we know that both the sack is pulled upwards in same time

so we will have

[tex]P = \frac{W}{t}[/tex]

so we will have

[tex]P = \frac{mgH}{t}[/tex]

[tex]P_1 = \frac{50(9.81)(2)}{t}[/tex]

[tex]P_2 = \frac{25(9.81)(4)}{t}[/tex]

so here in both cases we will have same power

Part b)

now lighter sack will move same distance in half time

so we will have

[tex]P_1 = \frac{50(9.81)d}{t}[/tex]

[tex]P_2 = \frac{25(9.81)d}{t/2}[/tex]

so again we have same power in above two cases

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