1. A particle moves along the x-axis. Its position varies with time and is given by equation x =-6t + 3t^2 where x is in metres and t is in seconds.
a) Sketch the position time graph for the particle between 0s and 4s.
b) What is the displacement of the particle after the first second?
c) What is the average velocity of the particle in the time interval ls to 3s?
d) What is the instantaneous velocity at 4s?
2. In the Hydrogen atom the electron and proton are separated by a distance of 5.3 x 10^-11m.
a) Find the gravitational force between them
b) Find the electrostatic force between them
c) Find the net force between them me= 9.11 x 10^-31kg mp=1.67x10^-27kg one unit of charge= 1.60 x 10^-19 C