# A motion of a Conical Pendulum

A ball is attached to a string and swung so that it travels in a horizontal circle.

Suddenly the angular velocity is increased. Will the angle with the vertical increase, decrease or stay the same? Justify your answer.

# A rod carries a charge uniformly distributed along its length

A rod of length L carries a charge Q uniformly distributed along its length.
Find the electrical field at point P on the axis of the rod, a distance a away from the end of the rod.

# The rod is “flying” above the cable

A conducting rod of length l, mass m, and resistance R is suspended by two vertical conducting wires of lengths d each. The circuit consists of a battery ε, the horizontal fixed wires, two parallel vertical wires , and the conducting rod. All conducting wires have negligible resistance and mass. There is a conducting long cable. The cable is below the rod and at a distance x.

# The equation of radioactive decay

The half-life of Molybdenum-93 is 4000 years. A sample of Molybdenum-93 has a mass of 10 mg. When will the mass be reduced to 1 mg?

Image Source: Virtual museum of chemical elements.

# A ball is attached to a string and swung so that it travels in a horizontal circle

A ball of mass 0.2 kg is attached to a massless string 1 m long and swung so that it travels in a horizontal circle of radius 0.5 m.

a) Draw a free-body diagram.
b) Find the force of tension in the string as the ball swings in a horizontal circle.
c) Find the period of the ball’s motion.

# To determine the acceleration due to gravity by means of a conical pendulum

A student conducted an experiment to measure the acceleration of gravity. He used a conical pendulum. The conical pendulum is a string with a bob (weight) that revolves around an axis through its point of suspension.