How does a pendalum conserve energy

Acar is traveling at 53.0 mi/h on a horizontal highway. (a) if the coefficient of static friction between road and tires on a rainy day is 0.104, what is the minimum distance in which the car will stop?

Why is alternating current more effective at long–distance travel than direct current? a. the power lines are made out of conductors. b. transformers increase or decrease voltage as needed. c. the ac generator is more efficient. d. ac has lower voltage than dc.

Aplanet of mass m 6.75 x 1024 kg is orbiting in a circular path a star of mass m 2.75 x 1029 kg. the radius of the orbit is r 8.05 x107 km. what is the orbital period (in earth days) of the planet tplanet?