A long plank xy is placed in the ground, a load of 120N is placed on it, at a distance of 0.50m from end X, as shown. End Y is lifted off the ground, The upward force needed to do this is 65N in the diagram, W is the weight of the plank, acting on its mid point what is the value of W
A.35N
B.47N
C.100N
D133N.

Estimate the kinetic energy of mars with respect to the sun as the sum of two terms, that due to its daily rotation about its axis, and that due to its yearly revolution about the sun. (assume mars is a uniform sphere with mass = 6.4×10 to the power of 23 kg, radius = 3.4×10 to the power of 6 m, rotation period = 24.7 hours, orbital period = 686 days and is 2.3×10 to the power of 8 km from the sun.)