7. In the fig below block A placed on block B. Block A weighs 3 N and Block B weighs 4 N. Block A attached to a wall by a string. A 30 N force applied to block B. The coefficient of kinetic friction µk between block A
and B is 0.3. Identify the forces acting on block A and find the tension in the string attached to block A?

1. Show ALL equations, then substitution of numerical values with units.

2. If you have a string of numbers with no preceding equation, sketch, or explanation, you will receive NO CREDIT even if it leads to the correct answer.

3. Make sure all symbols used are clearly identified on your sketch. BOX each required answer. Show work in a Logical Order – Don’t jump around.

How to tell if two objects are in thermal equilibrium 1.the objects have the same temperature 2.the objects are the same size 3.the objects are touching each other 4.the objects temperatures are changing

To understand the electric potential and electric field of a point charge in three dimensions consider a positive point charge q, located at the origin of three-dimensional space. throughout this problem, use k in place of 14? ? 0. part adue to symmetry, the electric field of a point charge at the origin must point from the origin.answer in one word.part bfind e(r), the magnitude of the electric field at distance r from the point charge q.express your answer in terms of r, k, and q. part cfind v(r), the electric potential at distance rfrom the point charge q.express your answer in terms of r, k, and q part dwhich of the following is the correct relationship between the magnitude of a radial electric field and its associated electric potential ? more than one answer may be correct for the particular case of a point charge at the origin, but you should choose the correct general relationship. a)e(r)=dv(r)drb)e(r)=v(r)rc)e(r)=? dv(r)drd)e(r)=? v(r)r

At what time will the interfering waves have an amplitudeof zero?