How much kinetic energy does a 7.2-kg dog need to make a vertical jump of 1.2 m? (the acceleration due to gravity is 9.8 m/s2.)

85 Joule (approx)

Potential energy at highest point

P.E = mgh = 7.2 kg × 9.8 m/s2×1.2 m≈85 Joule

This is the kinetic energy required for dog to jump a height of 1.2 m.

hope this helps!

the answer is f1 and d2 because if you put equal force on those two points the beam would balance trust me on this