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3 years ago

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Takes 5 seconds and 2,000 J for a crane to lift a very heavy object. Which of these correctly describes power and energy for thi

s action?
2,000 J of energy was converted into some other energy, requiring 10,000 W of power.
2,000 J of energy was converted into some other energy each second, requiring 400 W of power
2,000 J of power was converted into 400 W of energy.
2,000 J of power was converted into some other power every second, requiring 10,000 W of energy.

1 answer:

strojnjashka [21]3 years ago

8 0

Answer:

D

Explanation

take 5x2000 and J is the unit for power therfore it cant be A and B and C are not 10,000.

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Answer:

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where:

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v = velocity [m/s]

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where:

m1 = mass of the basketball = 0.5 [kg]

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m2 = mass of the tennis ball = 0.05 [kg]

v2 = velocity of the tennis ball before the collision = - 30 [m/s]

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Now replacing and solving:

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Before the engines fail, the rocket's altitude at time <em>t</em> is given by

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and its velocity is

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$1150\,\mathrm m=\left(80.6\dfrac{\rm m}{\rm s}\right)t+\dfrac12\left(3.90\dfrac{\rm m}{\mathrm s^2}\right)t^2$

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$y_2(t)=1150\,\mathrm m+\left(124\dfrac{\rm m}{\rm s}\right)t-\dfrac g2t^2$

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${v_f}^2-{v_i}^2=2a\Delta y$

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$v_2(32.6\,\mathrm s)=-196\frac{\rm m}{\rm s}$

That is, the rocket has a velocity of 196 m/s in the downward direction as it hits the ground.

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3 years ago