When an object slides across the floor, it is slowed down by friction and the floor surface gets warmer. what energy conversion
1 answer:
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Answer:
The bird has 20,000 times higher kinetic energy than the mosquito.
Explanation:
The formula for kinetic energy shows that the amount of energy is proportional to the mass:
The velocity of both objects being the same, the mass is the determiner. The ratio of the kinetic energy of the bird and the mosquito then becomes the ratio of their masses, i.e., 0.02kg/0.00001kg. The bird's energy is 20,000 times higher than that of the mosquito. This proportion becomes more believable if you imagine the event of a distracted errant bird colliding with your head, versus a confused mosquito colliding with your head.
Refer to the diagram shown below.
v = 35 km/h, the speed limit of the train
r = 150 m, the radius of the curve
ω = angular velocity
m = the mass of the strap
θ° = 15, the angle the strap makes with the vertical
T = tension in the strap
Note that
v = 35 km/h = 35*0.2778 m/s = 9.7223 m/s
The tangential velocity is v = rω, therefore the angular vcelocity is
ω = (9.7223 m/s)/(150 m) = 0.0648 rad/s
The centripetal force tending to make the train derail causes the strap to make an angle of 15 with the vertical.
Let θ = the maximum allowable angle at 35 km/h.
For horizontal equilibrium,
Tsin(θ) = mrω²
For vertical equilibrium,
Tcos(θ) = mg
Therefore
tan(θ) = (rω²)/g
= [(150 m)*(0.0648 rad/s)]/(9.8 m/s²)
= 0.0643
θ = tan⁻¹ 0.0643 = 3.7°
Because 15 > 3.7, we conclude that the train exceeded the 35 km/h speed limit when rounding the curve.
Answer: The train exceeded the 35 km/h speed limit.
v = 35 km/h, the speed limit of the train
r = 150 m, the radius of the curve
ω = angular velocity
m = the mass of the strap
θ° = 15, the angle the strap makes with the vertical
T = tension in the strap
Note that
v = 35 km/h = 35*0.2778 m/s = 9.7223 m/s
The tangential velocity is v = rω, therefore the angular vcelocity is
ω = (9.7223 m/s)/(150 m) = 0.0648 rad/s
The centripetal force tending to make the train derail causes the strap to make an angle of 15 with the vertical.
Let θ = the maximum allowable angle at 35 km/h.
For horizontal equilibrium,
Tsin(θ) = mrω²
For vertical equilibrium,
Tcos(θ) = mg
Therefore
tan(θ) = (rω²)/g
= [(150 m)*(0.0648 rad/s)]/(9.8 m/s²)
= 0.0643
θ = tan⁻¹ 0.0643 = 3.7°
Because 15 > 3.7, we conclude that the train exceeded the 35 km/h speed limit when rounding the curve.
Answer: The train exceeded the 35 km/h speed limit.
Answer:
The entropy change of the Universe that occurs is 19.346 J/K
Explanation:
Given;
temperature of the sun, = 5,300 K
temperature of the Earth, = 293 K
radiation energy transferred by the sun to the earth, E = 6000 J
The sun loses Q of heat and therefore decreases its entropy by the amount
The earth gains Q of heat and therefore increases its entropy by the amount
The total entropy change is:
Therefore, the entropy change of the Universe that occurs is 19.346 J/K