Physics please help
posted by Anonymous on .
While visiting Planet Physics, you toss a rock straight up at 13.6 m/s and catch it 3.50 s later. While you visit the surface, your cruise ship orbits at an altitude equal to the planet's radius every 340.0 minutes. What is the radius (in m) of the planet?
What is the mass (in kg) of the planet?

a) hf=hi+vi*t1/2 a t^2
solve for a given hf=hi, and t=3.5s
Now, solveing for a at radius planet, you know at orbiting altitude, it is 1/4 a (double distance.
1/4 a= v^2/2rp and v= (2PI*2rp)/period
or .25a=4PI^2*4*rp/2(334*60)
solve for rp.
Now mass. a= GM/rp solve for M 
I am still confused, there is no given hf or hi?