Chapter 1.3, Problem 34E

To determine

To find if the antelope is safe according to the given situation

Answer to Problem 34E

The antelope will be safe

Explanation of Solution

Given:

Speed of cheetah is 90 feet per second.

Speed of antelope is 60 feet per second.

Distance between the two when the encounter starts is 650 feet.

Formula Used:

Distance = Speed × Time

Consider the question:

If the cheetah can run at top speed for 20 seconds, then,

The distance travelled by cheetah in 20 seconds = (90 × 20) feet = 1800 feet

The distance travelled by antelope in 20 seconds = (60×20) feet = 1200 feet

Hence, according to the given condition:

Change in net distance between cheetah and antelope = (1800 - 1200) feet = 600 feet

Now, if the antelope has to be safe the change in distance should between the cheetah antelope should be less that the distance between the two when the chase started which was 650 feet in this case.

So, it is clear that, 600 feet < 650 feet.

Which means cheetah was still 50 feet short in distance to catch the antelope.

Conclusion:

Therefore, the antelope is safe and the statement given by my friend is incorrect.