Question

A spherical mass on the end of a string is spinning in a vertical circle about point P. Which of the forces acting on the mass contribute to the "centripetal force" when the mass is in position A? Select all that apply. The tension in the string. The force of gravity (weight). The force of drag (air resistance). Which of the forces acting on the mass contribute to the "centripetal force" when the mass is in position B, directly to the right of point P? The tension in the string. The force of gravity (weight). The force of drag (air resistance).

Answer 1

AT POSITION A:

---tension in the sting

--the force of gravity

REASON: Let the angle between the cable and wire is $\Theta$ then net force acting along the radial direction is F = mgcos$\Theta$ + T whcich is equal to the centripetal force

AT POSITION B:

----THE TENSION IN THE STRING IS ONLY CONTRIBUTE CENTRIPETAL FORCE

REASON: mg is the weight is vertically downwards and air drag is opposite to its motion so that air drag and weight acts tangentially but tension only acts along the radius and towards centre.