The pressure exerted by a phonograph needle on a record is surprisingly large. If the equivalent of 0.600 g is supported by a needle, the tip of which is a circle 0.240 mm in radius, what pressure is exerted on the record in N/m2?

Explanation:

Hello,

In this case, since pressure is defined as the force applied over a surface:

We can associate the force with the weight of the needle computed by using the acceleration of the gravity:

And the area of the the tip (circle) in meters:

Thus, the pressure exerted on the record turns out:

Which is truly a large value due to the tiny area on which the pressure is exerted.

Best regards.

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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f=ma a/f/m a= 480/60 a = 8m/s/s that is quick wow