А B
W
Figure 21-36 shows four
identical conducting spheres that are
actually well separated from one an-
other. Sphere W (with an initial
charge of zero) is touched to sphere Fig. 21-36 Problem 38.
A and then they are separated. Next, sphere W is touched to sphere
B (with an initial charge of -32e) and then they are separated.
Finally, sphere W is touched to sphere C (with an initial charge of
+48c). and then they are separated. The final charge on sphere W is
+ 18c. What was the initial charge on sphere .1?

As part of your daily workout, you lie on your back and push with your feet against a platform attached to two stiff springs arranged side by side so that they are parallel to each other. when you push the platform, you compress the springs. you do an amount of work of 79.0 j when you compress the springs a distance of 0.230 m from their uncompressed length. (a) what magnitude of force must you apply to hold the platform in this position? (b)how much additional work must you do to move the platform a distance 0.230 m farther? (c) what maximum force must you apply to move the platform a distance 0.230 m farther?

Atank has a shape of a cone with a radius at the top of 2 m and a height of 5 m. the tank also has a 1 m spout at the top of the tank. the tank is filled with water up to a height of 2 m. find the work needed to pump all the water out the top of the spout. (use 9.8 m/s2 for g and the fact that the density of water is 1000 kg/m3.)

Diverging mirrors and lenses always produce images