Aballoon rubbed against denim gains a charge of −7.0 µc. what is the electric force between the balloon and the denim when the two are separated by a distance of 3.0 cm? (assume that the charges are located at a point.) the value of the coulomb constant is 8.98755 × 109 n · m 2 /c 2 . include direction of the force. answer in units of n.

Matter is needed to transfer thermal energy bya. conductionb. convectionc. radiation d. both a & b.

Visualize the problem and identify special cases first examine the problem by drawing a picture and visualizing the motion. apply newton's 2nd law, ∑f⃗ =ma⃗ , to each body in your mind. don't worry about which quantities are given. think about the forces on each body: how are these consistent with the direction of the acceleration for that body? can you think of any special cases that you can solve quickly now and use to test your understanding later? one special case in this problem is if m2=0, in which case block 1 would simply fall freely under the acceleration of gravity: a⃗ 1=−gj^.

What would occur if the index of refraction of a material was less than n=1? the speed of light would increase to a speed larger than the maximum speed of light in a vacuum. the light wave would not bend at all though the material. the light wave would not be able to refract and would instead reflect off of the material. the speed of light would reduce to values close to 0 m/s.