In an amusement park ride known as Magic Mountain Superman, powerful magnets accelerate a car and its riders from rest to 45 m/s (about 160 km/h) in a time of 7.0 s. The mass of the car and its riders is 5.5 x 10 3 kg. Find the average net force exerted on the car and riders by the magnets.

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.

Which statement best describes who the period and frequency of electromagnetic was change between gamma rays and microwaves? a) the period and frequency stay the same. b) the period increases and the frequency decreases. c) the period decreases and the frequency increases. d) the period increases and the frequency increases.

Suppose that a comet that was seen in 563 a. d. by chinese astronomers was spotted again in year 1951. assume the time between observations is the period of the comet and take its eccentricity as 0.986. what are (a) the semimajor axis of the comet's orbit and (b) its greatest distance from the sun?