A sign on a National Forest road says: CAUTION! DANGEROUS CURVE AHEADóREDUCE(adsbygoogle = window.adsbygoogle || []).push({});

SPEED TO 20 MPH. One day, a particularly bright physics student gauged the coefficient

of friction between her tires and the road to be 0.40. Calling on her extensive knowledge

of physics and her skepticism of truth in advertising, she figured that the sign was there

to scare, not to protect, and that she could easily take the turn at 30 mph, a full 10 mph

above the posted speed limit. The turn was a tight one, 50 meters in radius.

A. Was the driver able to negotiate the turn? Why or why not?

B. How far (in mph) below the true speed limit was the posted speed limit?

C. If you take away friction, the turn would have to be banked. Find the necessary

angle for this banking, in order for our driver to safely negotiate the turn at 14

m/s.

Okay, so I'm having trouble realizing what information needs to be used and how. I found the centripetal acceleration to be 3.6 m/s^2...but without the mass of the car I'm drawing a blank as to how I can solve some of these. A point in the right direction would be great. Thanks!

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# Homework Help: Centripital force and acceleration

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