Homework 2 - Force & Energy

1. A 15g coin is placed on an old turntable, which rotates at only 30 rpm. If the coin just begins to slip on the turntable surface when it is placed 15cm from the center post, what is the tangential velocity and the coefficient of friction?

2. A small mass of 100g falls 50cm pulling a 0.4Kg block sitting on a table with a string guided by a pulley. If the acceleration was found to be 0.5 m/s^{2}, what is the coefficient of friction for the mass on the table? What was the final (maximum) velocity of the masses? (Note: Like your lab setup)

3. What is the force on a 10 kg orbiting satellite at 2 earth radii above the surface of the earth? (G=6.67 x 10^{-11} Nm^{2} / kg^{2} ; mass of earth = 6 x 10^{24} Kg ; radius of earth 6.38 x 10^{6} m)

4. A 5000Kg jet accelerates from rest to a final velocity of 100 m/s during take-off. What was the work done to accelerate the jet? If a force of 25000N was exerted to accelerate the jet, what was the distance it traveled on the runway?

5. A 3Kg ball is carried to the roof of a 50 m building. What was the work done against gravity? What will be the velocity the instant before the ball hits the ground when dropped from the roof?

6. A spring, with a spring constant of 50 N/m, is stretched 15 cm. What is the force and energy associated with this stretching?

7. A 1.0 kg mass glides along a smooth flat surface at 6 m/s until it encounters a surface with a 0.2 coefficient of friction. What is the distance travelled by the object and the work done by friction to stop it?

Subject | Science |

Due By (Pacific Time) | 06/08/2014 08:40 pm |

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