Solving Kinetic Energy: Mass, Velocity, and Jogger's Speed

[anglum]

kinetic energy?

a continent is 4200 km on a side and 32 km deep

its mass density is 2680 kg/m^3
it is moving at an avg speed of 4.8cm/year

what is its mass? answer in units of J

what is its kinetic energy? answer in units of J

a jogger with mass 75kg has the same kinetic energy as the continent... what is his velocity?? answer in units of m/s


i know the KE equation is KE = .5 * m * V^2

i am stuck on what my steps are with this problem... i know if i solve the first part the 2nd and 3rd parts will be easy becuz i plug them into the KE equation

 

[anglum]

to find the mass of the contintent i would take

Density = mass/volume

2680kg/m^3 = mass / (42000000m * 4200000m * 32000m)

and then solve for mass and that gives me the mass in kg?

 

[mshah3]

yes...exactly...then plug in for KE equation