Part A Sputnik The first artificial satellite to orbit the Earth was Sputnik I, launched October 4, 1957. The mass of Sputnik I was 83.5 kg, and its distances from the center of the Earth at apogee and perigee were 7330 km and 6610 km, respectively. Find the difference in gravitational potential energy for Sputnik I as it moved from apogee to perigee. AU = Submit Request Answer ? J Part A A block of wood has a steel ball glued to one surface. The block can be floated in a tank of water with the ball "high and dry" on its top surface. When the block is inverted, does the water level in the tank increase, decrease, or stay the same? increase decrease stay the same Submit Request Answer Part B Choose the best explanation from among the following: Inverting the block makes the block float higher in the water, which lowers the water level in the tank. The inverted block floats lower in the water, which displaces more water and raises the level in the tank. The same mass is supported by the water in either case, and therefore the amount of displaced water is the same. Submit Request Answer A child rocks back and forth on a porch swing with an amplitude of 0.260 m and a period of 2.60 s. Part A Assuming the motion is approximately simple harmonic, find the child's maximum speed. Umax = Submit Request Answer ? m/s