What is the answer to this question?
1 answer:
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Answer:
12.5 ft/s
Explanation:
Height of person = 6 ft
height of lamp post = 10 ft
According to the question,
dx / dt = 5 ft/s
Let the rate of tip of the shadow moves away is dy/dt.
According to the diagram
10 / y = 6 / (y - x)
10 y - 10 x = 6 y
y = 2.5 x
Differentiate both sides with respect to t.
dy / dt = 2.5 dx / dt
dy / dt = 2.5 (5) = 12.5 ft /s
Answer:
(a) 0
(b) 10ML
(c)
(d)
Explanation:
(a) When hanging straight down. The child is at the lowest position. His potential energy with respect to this point would also be 0.
(b) Since the rope has length L m. When the rope is horizontal, he is at L (m) high with respect to the lowest swinging position. His potential energy with respect to this point should be
where g = 10m/s2 is the gravitational acceleration.
(c) At angle from the vertical. Vertically speaking, the child should be at a distance of
to the swinging point, and a vertical distance of
to the lowest position. His potential energy to this point would be:
(d) at angle from the horizontal. Suppose he is higher than the horizontal line. This would mean he's at a vertical distance of
from the swinging point and higher than it. Therefore his vertical distance to the lowest point is
His potential energy to his point would be: