Q1. Scientists are working on a new system to kill cancer cells by zapping them with ultrahigh-energy (in the range of 10^12W) pulse of light that last for an extremely short time (a few nanoseconds). These short pulses scramble the interior of a cell without cause it to explode, as long pulses would do. We can model a typical such cell as a disk 5.0 micrometer in diameter, with the pulse lasting 4.0ns with an average power of 2.0x10^12W. We shall assume that the energy is spread uniformly over the faces of 100 cells for each pulse.

a). How much energy is given to the cell during this pulse?

b). what is the intensity (in W/m^2) delivered to the cell?

c). what are the maximum values of the electric and magnetic fields in the pulse?

Q2. A 500 g rubber ball is dropped from a height of 10 m and undergoes a completely elastic collision with the earth.

a) What is the earth's velocity after the collision?

Imagine the earth was at rest just before the collision.

b) How many years would it take the earth to move 1.0 mm at this speed?