Amotorist drives north for 36.0 minutes at 96.0 km/h and then stops for 15.0 minutes. he then continues north, traveling 130 km in 2.20 h. (a) what is his total displacement? km
(b) what is his average velocity? km/h

a)

b)

Explanation:

First we convert our minutes to hours so we work always in the same units.

Where we used the fact that 1 hour are 60 min, thus the multiplying factor is equal to 1 (not altering the time, just changing the units).

a) On the first part the motorist travels a distance , and on the second part he travels .

The total displacement is

b) The average velocity is the relation between the total displacement and the time taken to cover it. Our total time is t=0.6h+0.25h+2.2h=3.05h, thus we have:

r=rho l/a where a is the area, l is the length and rho is resistivity so the greater the area the lesser the resistance thats why the earth pin is thicker bcos current follow the shortest path, so less resistive .

b

explanation: