What would be the weight of a 59.1-kg astronaut on a planet with the same density as earth and having twice earth's radius? . i am getting 290, but i dont know if that is . a) 580n. b) 290n. c) 1160n. d) 2320n. e) 1200n

The astronaut's weight on the Earth's surface can be  determined from  
F = m g = 579.2 N subsituting  mass equal to 59.1 kg and acceleration due to gravity equal to 9.8 m/s². When the variables are mass of the earth and the radius of the earth, F = k m / r². Thus, doubling the mass of the earth would double his weight and doubling the radius would decrease the original weight by 1/4.  Hence, 579.2 N* 2* 1/4 equal to 290 N. Answer is B.

Velocity=total displacement/timefrom house to store is 500 from store to neighbor is 200 therefore total displacement=500+200=700metrestherefore,700metres/910seconds=0.8metres per second

Answerthe energy required is 1.60 × 10⁻¹⁸ j, to three significant figures.explanationwe define electric potential as the ratio electric potential energy to the charge,    then the following gives us the potential difference,      the formula  may be on your formula sheet.the change in electric potential energy would be the energy that would needed to move it from point a to point b. solving for that, we get    using q = 8.00  × 10⁻¹⁹ c and  δv = 2.00 v, we get    the energy required is 1.60 × 10⁻¹⁸ j, to three significant figures.