Which of the following is not a characteristic of electromagnetic waves? (A) They can travel at various speeds through any one m
2 answers:
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The momentum increases by a factor of 2
Explanation:
We can solve this problem by rewriting the momentum of the rocket in terms of the kinetic energy and the mass.
The kinetic energy of the rocket is:
(1)
where
m is the mass
v is the velocity
The momentum of the rocket is
(2)
From eq.(1) we get
and substituting into (2),
Now in this problem we have:
- The kinetic energy of the rocket is increased by a factor 8:
- The mass is reduced by half:
Substituting, we find the new momentum:
So, the momentum increases by a factor of 2.
Learn more about momentum and kinetic energy:
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Answer:
(a)10.5 rad/s2
(b) 20.9 rev
(c) 47.27 m
Explanation:
As the block of mass 53 kg is falling and pulling on the rope. The tension force on the rope must be equal to the gravity acting on the block according to Newton's 3rd law
T = mg = 53*9.81 = 519.93 N
Since this tension force would rotate the cylinder freely without any friction. The torque created by this tension force is
To = TR = 519.93 * 0.36 = 187.17 Nm
This solid cylinder would have a moment of inertia around it's rotating axis of:
(a)We can use Newton's 2nd law to calculate the angular acceleration exerted by such torque on the solid cylinder
(b) With such constant angular acceleration, the angle it would make after 5s is
Since each revolution equals to of angle, we can calculate the number of revolution it makes
(c) Assume the thickness of the rope is negligible (and its wounded radius is unchanging), we can calculate the rope length unwinded after rotating 131.3rad