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idontknow19
Sep 4, 2010, 09:40 AM
Hope you can help me to solve this problem.thank you for your effort

A car is traveling at 50km/hr on a road such that the coefficient of friction between its tires and the road is 0.50.What is the maximum turning radius of the car?




A 3.2 pound stone at the end of the string 2.0 feet long is whirled in a vertical circle. The tension in the string is 5.0pound when the stone is at the top of the circle.What is the velocity of the stone?

Unknown008
Sep 5, 2010, 10:16 AM
(a) I assume the mass of the car is m kg.

The maximum value for the frictional force is given by:

Frictional\ Force = \mu R = 0.5 (m \times 9.8) = 4.9m\ N

Now, we know that in circular motion, the centripetal force is given by:

F = \frac{mv^2}{r}

You have F, which is the centripetal force the frictional force provides,
m is the mass of the car,
v is the speed of the car in m/s
r is the turning radius.

Solve for r.

(b) F = \frac{mv^2}{r}

We know that the centripetal force here is given by the (Tension + Weight of stone).
We know the mass of the stone, just convert to kg.
We know the radius of the motion, just convert into metres.

Solve for v the speed of the stone.

Post what you get! :)