can someone pls explain this

10. 11. 12. 13. 14. 15. A white dwarf star has a density of 1.0 x 109 lag/m3. [fits radius is the same as that of the Earth. what is the gravitational acceleration at its surface. 9'? (a) 1.8 x 106 ms'2 (b) "L7 x 105 ms"2 (c) 2.2 x 10 ms-2 ((1) 5.5 x mums-9 (e) 6.4 x 10" m 5'2 A space station is in a circular orbit around the Eanlt. Its altitude is equal to one third of the Earth's radius. What is the acceleration due to gravity at this altitude? (a) 38.2 m s\"2 (b) 5.51 m 5'2 (c) 9.80 m 5'2 (d) 0.65 m s'2 (e) 2.37 m s'2 Following from the previous questions, what is the space station's period of revolution around the Earth? (a) 130 min (b) 83 min (c) 290 min (d) 420 min (e) 37 min The following three questions relate to the following information. The distance between the centres of the earth and moon is 3.85 x 105 km. The moon's period of revolution around the earth is 27.3 days. What is the tangential speed of the moon? (a)1.02ms'1 (b) 1.02 x 105ms'1 (c) 1.02 x 102ms'1 (cl) 1.02 x 101 ms-1 (13) 1.02 x lll3ms'1 What is the distance the moon travels in one day? (a) 8.861011 (b) 3.86 x 104 km (c) 3.86 x 101 km (d) 3.36 x 107 km (e) 3.86 x 103 km Through what angle (in degrees) will the moon move in one day? (a) 93 (b) 132 (1:) 16.7\" (d) 21 .3 (e) 26.4\" 27