An aluminum (E = 10 x 106 lb/in2, ν = 0.333) bar of length (L = 49 inch) has a circular cross-section of radius (r = 0.7 inch).
1 answer:
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By the work energy theorem, the total work done on the stone is given by its change in kinetic energy,
We have
Then the total work is
Answer:
Both balls hit the ground at the same time
Explanation:
Adam drops the ball from rest, so the ball just "<em>falls</em>" in vertical direction, being gravity its only acceleration, for cinematic movements we use that:
In this case we have that gravity is negative, and as Adam drops the ball,
Bob throws the ball horizontally, so the movement will be a <em>parabola</em>, we can divide into horizontal direction, and vertical direction.
But we only need to analize the vertical movement, in wich again the only acceleration is gravity, and compare it with Adam's ball. Again we have that gravity is negative, and as the initial throw is horizontal,
Finally, we have that
where
both for Adam's vertical drop, and for Bob's vertical component of the parabolic throw.
Now, if we put (the origin of the vertical coordinate), we get for both cases that
where we can clear the value for the time t, of the fall, wich will be the same in both cases.
Hence, both balls hit the ground at the same time.
Answer:
b. Decreases
Explanation:
The total resistance of a series circuit is equal to the sum of the individual resistances:
(1)
Therefore, as we add more lamps, the total resistance increases (because we add more positive tems in the sum in eq.(1).
The current in a circuit is given by Ohm's law:
where V is the voltage provided by the power source and is the total resistance. We notice that the current, I, is inversely proportional to the total resistance: therefore, when more lamps are added to the series circuit, the total resistance increases, and therefore the current in the circuit decreases.