Which has the greatest amount of energy: ultraviolet rays, infrared rays, or
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Complete part of Question: What is Jane's (and the vine's) angular speed just before she grabs Tarzan
Answer:
Jane's (and the vine's) angular speed just before she grabs Tarzan, w = 1.267 rad/s
Explanation:
According to the law of energy conservation:
Total change in kinetic energy = Total change in potential energy
Mass of Jane = 60 kg
Mass of the vine = 32 kg
Mass of Tarzan = 72 kg
Height of Tarzan = 5.50 m
Length of the vine = 8.50 m
Jane's change in gravitational potential energy,
Vine's gravitational potential energy,
Vine's Kinetic energy :
Jane's Kinetic energy:
3234 + 862.4 = 2167.5w² + 385.33w²
4096.4 = 2552.83w²
w² = 4096.4/2552.83
w² = 1.605
w = √1.605
w = 1.267 rad/s
Answer:
<em>60008.4 J</em>
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Explanation:
The mass of each kid = 30 kg
mass of the cart = 20 kg
The speed of the cart down the hill = 30 km/hr = 30 x 1000/3600 = 8.33 m/s
The height of the hill = 80 m
The potential energy of the boys at the top of the hill = mgh
where
m is the total mass of the kids and the cart = (30 x 2) + 20 = 80 kg
g is the acceleration due to gravity = 9.81 m/s^2
h is their height above the ground = 80 m (on the top of the hill)
substituting, we have
potential energy PE = 80 x 9.81 x 80 = 62784 J
At an instance at the bottom of the hill
their kinetic energy =
where
v is their velocity = 8.33 m/s
m is their total mass = 80 kg
substituting, we have
kinetic energy KE = = 2775.6 J
Total work done on the cart is equal to the energy lost by the cart when it reached the bottom of the hill
work done by friction = PE - KE = 62784 - 2775.6 = <em>60008.4 J</em>