Question

Two children who are bored while waiting for their flight at the airport decide to race from one end of the 20-m-long moving sidewalk to the other and back. Phillippe runs on the sidewalk at 2.0 m/s (relative to the sidewalk). Renee runs on the floor at 2.0 m/s. The sidewalk moves at 1.5 m/s relative to the floor. Both make the turn instantly with no loss of speed. a. Who wins the race

Answer 1

Renee will win the race

Step-by-step explanation:

Total time of motion for Phillippe is given as

`t_1 = (L)/(v + v_1 ) + (L)/(v - v_1)`

now we have

`t_1 = (L)/(2 + 1.5) + (L)/(2 - 1.5)`

`t_1 = (L)/(3.5) + (L)/(0.5)`

`t_1 = 2.28 L`

now for Renee we have

`t_2 = (L)/(2) + (L)/(2)`

`t_2 = L`

so here we can see that

`t_2 < t_1`

so Renee will win the race