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

ballstringswung.jpgA 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.

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The quantum tunneling phenomenon


The quantum tunneling phenomenon is negligible in the classical mechanics.

Show that the tunneling probability equals 0 for an object of mass 0.007 kg moving at a speed of 0.1 m/s against a solid obstacle of height 0.05 m and width 0.01 m.

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A car moves around a curved banked road


A curved road is banked at an angle β, and there is no friction between the road and the car’s tires. The road has a radius of curvature of 50 m.
A car has a speed of 90 km/h.

Find angle β.

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The car passes over the top of a convex bridge


A car has a mass of 1500 kg and travels with a speed of 5 m/s. The car passes over the top of a convex bridge that has a radius of curvature equal to 10 m. What is the force of the bridge on the car as it passes over the top?

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A C-130 Hercules is traveling toward a cliff

Mission highlight

A C-130 Hercules is traveling toward a cliff at the speed of 150 m/s. Its engines emit a tone at frequency f0. We consider that the speed of sound is 340 m/s. What frequency is received by a pilot after reflection from the cliff?

Image Source: U.S. Air Force
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To determine the acceleration due to gravity by means of a conical pendulum

ExpConPenA 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.
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A string around the Earth’s equator


Place a string around the Earth’s equator and pull it snug. Add a length of one meter to the string and push it away from the equator an equidistant amount. What is the largest animal, from the list below, that would now be able to walk under the string?

Flea Mouse Dachshund Calf Horse Elephant
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