Physics: If a pulley with six supporting ropes is used to lift a 1200 lb piano, what input force is needed? a 1800 lbs b 500 lbs c 300 lbs d 200 lbs

If a pulley with six supporting ropes is used to

jak000067oyyfia

04.01.2022

D) 200 Lb

Explanation:

As we know that the piano is balanced by six ropes connected to it

by the force balance we can say that tension force of all ropes will combined to balance the weight of the object

So here we can say by force equation we will have

6T = mg

so we will have

$T = \frac{mg}{6}$

here we know that

mg = 1200 lb

so we will have

$T = \frac{1200}{6} = 200 lb$

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naiajNan

16.11.2020

1.6 kJ

Explanation:

Given

mass of truck $m=200\ kg$

speed of truck $v=4\ m/s$

We know kinetic Energy is the energy possessed by a moving body such that its value is given by product of mass and square of speed.

$K.E.=\frac{1}{2}mv^2$

$K.E.=\frac{1}{2}\times 200\times (4)^2$

$K.E.=100\times 16$

$K.E.=1600\ J\approx 1.6\ kJ$

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