During the winter an aluminium part was brought from the outdoor to the workshop. How much heat was received by the 0.43 t aluminium part if the outdoor temperature is -4 Celsius and the workshop air temperature is 17 celsius . Enter results in megajoules rounded to one decimal place

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?