The region around an electric charge that will apply force to other charges

Two identical stars with mass m orbit around their center of mass. each orbit is circular and has radius r, so that the two stars are always on opposite sides of the circle. (a) find the gravitational force of one star on the other. (b) find the orbital speed of each star and the period of the orbit. (c) how much energy would be required to separate the two stars to infinity?

A2.50 × 105 w motor is used for 26.4 s to pull a boat straight toward shore. how far does the boat move toward shore if a force of 4.20 × 104 n is applied by the motor?

Aweather forecaster uses doppler radar to predict the track of a storm near the town of meadowlands. when the doppler signal is pointed at the storm from the town's center, the frequencies of the waves appear to be decreasing. what should the weather forecaster predict? a. that the storm will move around the edges of meadowlands without hitting the tosis center o b. that residents should be prepared, because it is impossible to know whether the storm will hit o c. that the storm is moving toward meadowlands and that residents should be prepared d. that the storm is moving away from meadowlands and is not likely to hit the town