1 hour=3600 seconds
1 mile=5280 feet
87 miles/hr (1 hr/3600 sec)(5280 ft/mile)=127.6 feet/sec
Distance= Rate*time
d=127.6(12)=1531.2 feet (after 12 seconds)
I would say 120 since it’s not at the end near 170
Answer:
a) -13.9 ft/s
b) 13.9 ft/s
Step-by-step explanation:
a) The rate of his distance from the second base when he is halfway to first base can be found by differentiating the following Pythagorean theorem equation respect t:
(1)

(2)
Since:

When x = 45 (the batter is halfway to first base), D is:

Now, by introducing D = 100.62, x = 45 and dx/dt = 31 into equation (2) we have:

Hence, the rate of his distance from second base decreasing when he is halfway to first base is -13.9 ft/s.
b) The rate of his distance from third base increasing at the same moment is given by differentiating the folowing Pythagorean theorem equation respect t:

(3)
We have that D is:

By entering x = 45, dx/dt = 31 and D = 100.63 into equation (3) we have:

Therefore, the rate of the batter when he is from third base increasing at the same moment is 13.9 ft/s.
I hope it helps you!