A skier has an acceleration of 2.5 m/s2. How long does it take her to come to a complete stop from a speed of 18 m/s? A. 3.4 s B
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Answer:
the rate of the change of the length of the shadow is - 0.8625 m/s.
The negative(-) sign means the length of the shadow decreases at a rate of 0.8625 m/s.
Explanation:
Given the data in the question;
Let x represent the man's distance from building,
initially x = 1m2
dx/d t= -2.3 m/s
Also Let y represent shadow height
so we determine dy/dt when x is 4m from the building
form the image description of the problem, we see two-like triangles with the same base and height ratios
so
2 / (12-x) = y / 12
24 = y(12 - x )
y = 24 / (12-x)
dy/dt = 24/(12-x)² × dx/dt
Now at x = 4,
we substitute
dy/dt will be;
⇒ 24/(12 - 4)² × -2.3
= 24/64 - 2.3
= 0.375 × -2.3
dy/dt = - 0.8625 m/s
Therefore, the rate of the change of the length of the shadow is - 0.8625 m/s.
The negative(-) sign means the length of the shadow decreases at a rate of 0.8625 m/s.
The magnitude of the average impulsive force imparted to the ball if it is in contact with the bat is 6000 N
The mass of the baseball, m = 0.15 kg
The speed at which it moves, v = 30 m/s
Time at which the baseball was in contact with the bat, t = 0.75 ms
t = 0.75/1000 s
t = 0.00075 s
The impulsive force is given by the formula:
Substitute m = 0.15 kg, v = 30, and t = 0.00075s into the formula above:
The magnitude of the average impulsive force imparted to the ball if it is in contact with the bat is 6000 N
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