Question

In Speed Study Number 1, we looked at two cars traveling the same distance at different speeds on city streets. Car "A" traveled at a speed of 35 miles per hour. Car "B" traveled at 45 miles per hour. Both cars traveled a distance of 10 miles.
How much sooner did Car "B" arrive at its destination than Car "A"?
a-90 seconds
b-about 5 minutes
c- about 10 minutes

Answer 1

Answer:

b-about 5 minutes

Step-by-step explanation:

For an object in uniform circular motion (=moving at constant velocity), the time taken to cover a certain distance is given by:

$t=\frac{d}{v}$

where

d is the distance covered

v is the speed of the object

In this problem we have:

d = 10 miles is the distance covered by both cars

Car A travels at a speed of

$v_A=35 mi/h$

So the time it takes is

$t=\frac{10}{35}=0.286 h \cdot 60 \frac{min}{h}= 17.2 min$

Car B travels at a speed of

$v_B=45 mi/h$

So the time it takes is

$t'=\frac{d}{v_B}=\frac{10}{45}=0.222 h \cdot 60 \frac{min}{h}=13.3 min$

So the difference in time is

$\Delta t = t-t'=17.2 min - 13.3 min \sim 4 min$

So, the closest answer is

b-about 5 minutes