A person carries a plank of wood long 2m with one hand pushing down on it at one end with a force F1 and the other hand holding it up with a force of F2 applied at a distance of 50 cm from the same end of the plank. The plank has a mass of 20 kg and its centre of gravity is at the middle of the plank.

What are the magnitue of F1 and F2?

Two charged particles, q1 and q2, are located on the x-axis, with q1 at the origin and q2 initially at x1 = 12.2 mm. in this configuration, q1 exerts a repulsive force of 2.62 µn on q2. particle q2 is then moved to x2 = 18.0 mm. what is the force (magnitude and direction) that q2 exerts on q1 at this new location? (give the magnitude in µn.)