A man pulls a wagon at a 15 degree angle above the horizontal using the wagon’s handle. The man applies a force of 80 N on the wagon, which has a mass of 6.5 kg. The wagon rolls at a constant speed. Find the coefficient of friction between the wagon wheels and the ground.

Two conductors, a and b, are each in the shape of a tetrahedron. but of different sizes. they are charged in the following manner: 1. tetrahedron a is charged from an electrostatic generator to charge q. 2. tetrahedron a is briefly touched to tetrahedron b. 3. steps 1 and 2 are repeated until the charge on tetrahedron b reaches a maximum value. if the charge on tetrahedron b was q/4 after the first time it touched tetrahedron a. what is the final charge qbmax on tetrahedron b?