If she returned home by the same path 7 h 30 min after she left, what were her average speed and velocity in km/h for the entire trip

speed  v = 0.148 m / s

velocity   v = 0

Explanation:

In this exercise we must be careful that the speed is a scalar and the speed is a vector, let's start by looking for the speed

           v = Δx /Δt

the distance traveled is x = 2d and the time taken is

           t = 7h 30 min

let's reduce to seconds

          t = 7 h 3600s / 1h + 30 min 60s / 1min = 27000 s

so the speed is

          v = 2d / 27000

to finish the calculation suppose a distance traveled d = 2000 m

          v = 2 2000/27000

          v = 0.148 m / s

this is the raides which is the speed module

Velocity is a vector,

          v = Dx / Dt

in this case the displacement is

           Dx = d -d

           Dx = 0

the total displacement is zero since it returns to the starting point, consequently the velocity is zero

          v = 0

bold is a vector

b.

explanation:

10.0

a.   mass number from atomic number