A dancer starts 3 meters from the curtain then moves 8 meters from the curtain in 15 seconds. What was his velocity?
1 answer:
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Answer:
m = 236212 [kg]
Explanation:
The potential energy can be determined by means of the product of mass by gravity by height. In this way, we have the following equation.
where:
P = potential energy = 3360000000 [J]
m = mass [kg]
g = gravity acceleration = 9.81 [m/s²]
h = elevation = 1450 [m]
Now, we can clear the mass from the equation above:
Answer:
570 N
Explanation:
Draw a free body diagram on the rider. There are three forces: tension force 15° below the horizontal, drag force 30° above the horizontal, and weight downwards.
The rider is moving at constant speed, so acceleration is 0.
Sum of the forces in the x direction:
∑F = ma
F cos 30° - T cos 15° = 0
F = T cos 15° / cos 30°
Sum of the forces in the y direction:
∑F = ma
F sin 30° - W - T sin 15° = 0
W = F sin 30° - T sin 15°
Substituting:
W = (T cos 15° / cos 30°) sin 30° - T sin 15°
W = T cos 15° tan 30° - T sin 15°
W = T (cos 15° tan 30° - sin 15°)
Given T = 1900 N:
W = 1900 (cos 15° tan 30° - sin 15°)
W = 570 N
The rider weighs 570 N (which is about the same as 130 lb).
