If you moved to a planet that has the same mass as the earth but twice the diameter, how would your weight be affected?

(a) assume the equation x = at^3 + bt describes the motion of a particular object, with x having the dimension of length and t having the dimension of time. determine the dimensions of the constants a and b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.) (b) determine the dimensions of the derivative dx/dt = 3at^2 + b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.)

Mechanical energy is when the amount of kinetic and potential energies added together remains the same. conserved created lost

If anyone who can me with this hw? i would really appreciate it