In the form of Millikan's experiment, an oil drop was observed to fall with a const
velocity of 2.5 x 10*ms in the absence of an electric field. When a p. d of 1000V
applied between the plates 10mm apart, the drop remained stationary betwe
them. If the density of oil is 9 x 10²kgm", density of air is 1.2kgm and viscosity
air is 1.8 × 10-Nsm-. Calculate the radius of the oil drop and the number of elec
charges it carries.

Molten iron fills a mould, which has a volume of 200 cm cubed. calculate the volume when the iron cools and solidifies. molten iron has a density of 7.0g/cm cubed. in its solid state, iron has a density of 8.0g/cm cubed.

What’s #16 asking me and how do i solve it?

Arunner is jogging at a steady 3.6 km/hr. when the runner is 2.9 km from the finish line, a bird begins flying from the runner to the finish line at 14.4 km/hr (4 times as fast as the runner). when the bird reaches the finish line, it turns around and flies back to the runner. even though the bird is a dodo, we will assume that it occupies only one point in space, i.e., a zero-length bird. how far does the bird travel? (b) after this first encounter, the bird then turns around and flies from the runner back to the finish line, turns around again and flies back to the runner. the bird repeats the back and forth trips until the runner reaches the finish line. how far does the bird travel from the beginning? (i.e. include the distance traveled to the first encounter)