Other Physics Answers

A man stands on a freely rotating platform. With his arms extended, his rotation frequency is 0.25 rev/s. But when he draws them in, his frequency is 0.8 rev/s. Find the ratio of his moment of inertia in the first case to that of the second.

The force due to weight of a certain flywheel is 5000 lb, having a radius of gyration of 3 ft. If there is a a driving torque of 600 lb - ft and a resisting torque of 250 lb - ft, find the time to increase its speed from 20 rev/min to 80 rev/min. (Hint : The moment of inertia is directly proportional to the square of radius of gyration, having the constant of proportionality to be the mass of the system.)

A certain flywheel is acted upon by a constant torque of 45 N-m. Find the time it takes to go from rest to an angular velocity of 812 rev/min if the moment of inertia is 5 kg-m2?

What is the velocity of a shot put with a mass of 7.3 kg and momentum of 22 kg -m/s moving in the forward direction?

Provide and explain the source of attenuation in a silica optical fiber with regard to wavelength used. 

Peng Nepomuceno, a world renowned bowler holds a 12 pound bowling ball that is held 5 ft above the floor. A.) Calculate the GPE of the bowling ball. B.) If the crate were lifted by a crane to a height of 25m, how much work is done?

Propose a problem of a mixed circuit (minimum of 5 resistors) where you need to apply Ohm’s Law and Kirchhoff’s Law for its solution.

YOU NEED TO SOLVED

If you lift a box using a 100 J of work within 5 s, how much power has been done? How much is the power if it’s lifted using a 10 J of work?

A car travelling south at 36 m/s sounds a 456 Hz horn.

(a) What frequency is heard by the driver in an approaching truck traveling north at 25 m/s?

(b) What frequency is heard by the driver if he is heading south away from the car at 25 m/s?

A simple pendulum is found to vibrate 50 times within 200 s. When 1.5 m of its length is reduced to a certain length, it vibrates 50 times in 175 s. Find the original length of the pendulum.