15. margie, who weighs sqan, is standing on a bathroom scale that Weighs 47.ON. " With what magnitude force does the a scale push up on margie ? ( b ) with what magnitude force does the floor Push up on the scale ? 19. The radius of Earth is 6. 371 x 10' km ( a) Find the altitude above Earth's surface Where Earth's gravitational field strength Would be two thirds of its Value at the surface ( b) Find the altitude above Earth's surface Where Earth's gravitational field strength would be one - fifth of its value at the Surface 21 . What is the ratio of Earth's grantational force on a satellite when it is on the ground to the gravitational force exerted When the Satellite is Orbiting at an altitude of 809 km