Answer: 71.7 KJ
Explanation:
The rotational kinetic energy of a rotating body can be written as follows:
Krot = ½ I ω2
Now, any point on the rim of the flywheel, is acted by a centripetal force, according to Newton’s 2nd Law, as follows:
Fc = m. ac
It can be showed that the centripetal acceleration, is related with the angular velocity and the radius, as follows:
ac = ω2 r
We know that this acceleration has a limit value, so , we can take this limit to obtain a maximum value for the angular velocity also.
As the flywheel is a solid disk, the rotational inertia I is just ½ m r2.
Replacing in the expression for the Krot, we have:
Krot= ½ (1/2 mr2.ac/r) = ¼ mr ac = ¼ 67.0 Kg. 1.22 m . 3,510 m/s2 = 71. 7 KJ
ANSWER - (1) are constantly moving (2) have volume (3) have intermolecular forces (4) undergo perfectly elastic collisions (5) have an average kinetic energy proportional to the ideal gas’s absolute temperature
The energy of a photon is given by
where
is the Planck constant
f is the frequency of the photon
In our problem, the frequency of the light is
therefore we can use the previous equation to calculate the energy of each photon of the green light emitted by the lamp:
The density of the object is the ratio of its mass and volume. From the given dimensions above, we determine the volume through the equation,
V = L x W x H
Substituting,
V = (3 cm)(2 cm)(1 cm) = 6 cm³
From the idea presented above,
d = m/V
Substituting the known values,
d = (30 g)/ (6 cm³) = 5 g/cm³
ANSWER: 5 g/cm³
Answer:
25 meters = 1 minute
505 meters = ? minutes
Therefore, 505/25
Therefore, 101/5
Therefore, 2.2 minutes
It moves 505 meters in 2.2min
