Answer:
-390 mph
Step-by-step explanation:
Let a and b represent, respectively, the distances of A and B from the airport. The distance d between the planes is then given by the Pythagorean theorem as ...
d² = a² + b²
Differentiating with respect to time, we have ...
2d·d' = 2a·a' +2b·b'
Solving for d', we get ...
d' = (a/d)a' +(b/d)b'
The value of d at the time of interest is ...
d = √(a² +b²) = √(30² +40²) = √2500 = 50
Then the rate of change of separation is ...
d' = (30/50)(-250 mph) +(40/50)(-300 mph) = (-150 -240) mph
d' = -390 mph
The distance between planes is decreasing at 390 miles per hour.
B i got u u got any more i can help you
Answer:
The sidewalk moves at 0.5 ft/sec
Josie's speed walking on a non-moving ground is 3.5ft/sec
Step-by-step explanation:
Let x represent the speed of the side walk and y represent her walking speed
It takes Jason's 8-year-old daughter Josie 44 sec to travel 176 ft walking with the sidewalk
Distance = speed × time
176 = (x+y)×44
44x+44y = 176
x+y = 4 .......1
It takes her 7 sec to walk 21 ft against the moving sidewalk in the opposite direction).
21 = (y-x)7
7y - 7x = 21
y - x = 3 ......2
Add equation 1 to 2
2y = 7
y = 3.5 ft/sec
From equation 1
x + y = 4
x = 4 - 3.5 = 0.5
x = 0.5 ft/sec
The sidewalk moves at 0.5 ft/sec
Josie's speed walking on a non-moving ground is 3.5ft/sec
