An athlete leaves one end of a pool of length l at t = 0 and arrives at the other end at time t1. she swims back and arrives at the starting position at time t2. if she is swimming initially in the positive x direction, determine her average velocities symbolically in the first half of the swim, the second half of the swim, and the round trip. (assume that time t2 is from the other end of the pool to the starting point. use any variable or symbol stated above as necessary. indicate the direction with the sign of your answer.)

Average velocity is defined as

now we have

when she cross the pool in time t1

when she cross the pool back to starting position

Here negative sign is for its return path direction which is reversed of its initial direction.

now for the round trip

displacement = 0

so v = 0

the order for strong to weak forces such as

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force

the fundamental forces are those forces that act between to objects or element to make interactions. there are four types of fundamental forces such as strong and weak nuclear forces (due to protons and electrons), electromagnetic force (due to the motion of electrons) and gravitational force (due to orbital movement of the planet). if these forces are arranged on the basis of their maximum strength then the order is

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force