Mantle I think idrk cuz of erosion
Answers:
a) 
b) 
c) 
Explanation:
<h3>a) Mass of the continent</h3>
Density
is defined as a relation between mass
and volume
:
(1)
Where:
is the average density of the continent
is the mass of the continent
is the volume of the continent, which can be estimated is we assume it as a a slab of rock 5300 km on a side and 37 km deep:

Finding the mass:
(2)
(3)
(4) This is the mass of the continent
<h3>b) Kinetic energy of the continent</h3>
Kinetic energy
is given by the following equation:
(5)
Where:
is the mass of the continent
is the velocity of the continent
(6)
(7) This is the kinetic energy of the continent
<h3>c) Speed of the jogger</h3>
If we have a jogger with mass
and the same kinetic energy as that of the continent
, we can find its velocity by isolating
from (5):
(6)
Finally:
This is the speed of the jogger
First change km/ s into m/s, then use the formula
Lambda = velocity/ frequency
A)Ep'=mgh=mgl(1-cosa).At the bottom of the swing Ep=0(reference level),so the potential energy as the child is just released is bigger than the potential energy at the bottom of the swing.;B)The speed of the child at the bottom of the swing-->v=√(2gh)=√[2gl(1-cosa)];C)I don't think that the tension does any work.