55 J
Explanation:
Kinetic energy is given as: 0.5MV^2 where M is the mass and V is the speed of rotation. Since the masses are point masses, we calculate the point mass for each mass.
M1 = 30*0.2^2 = 1.2kgm^2
M2 = 20*0.4^2 = 3.2kgm^2
V = 5 rad/s
Calculating using the formula above, we obtain :
0.5(1.2+3.2)5^2 =0.5*4.4*25 = 55 J
Inclined plane is a simple machine that is a straight slanted surface.
The period of a simple pendulum is given by:

where L is the pendulum length, and g is the gravitational acceleration of the planet. Re-arranging the formula, we get:

(1)
We already know the length of the pendulum, L=1.38 m, however we need to find its period of oscillation.
We know it makes N=441 oscillations in t=1090 s, therefore its frequency is

And its period is the reciprocal of its frequency:

So now we can use eq.(1) to find the gravitational acceleration of the planet:
Since force is mass*acceleration,
F = 70kg * 9.8 m/s