If a 340 n girl sits on a seesaw and is lifted 1.4 m in 1.6 s, how much work was done by the child on the other side?

Can anybody me with this? ? (picture included.)

Find the magnetic field a distance r from the center of a long wire that has radius a and carries a uniform current per unit area j in the positive z direction.

Use the profile illustrated for problem (1). assume that the layer of silty sand fill (sm) is placed over the entire site. estimate the thickness of the fill (h - in feet) that will cause the effective vertical stress at the center of the clay layer to increase by 517.5 pounds per square foot.