Generally, rings form from moons, asteroids, or comets that have disintegrated due to a collision or because they got too close to their planet (Roche Limit). ... Most of the debris, however, will not have enough energy to overcome the planet's gravity and will remain in orbit around the planet.
Answer:
Part a)

Part b)

Explanation:
As we know that the see saw bar is massless so here torque due to two masses is given as

here we will have

now we will have inertia of two masses given as

now we have

now the angular acceleration is given as

so we have

Part b)
Now if the rod is not massles then we will have total inertia given as

so we will have

now the acceleration is given as


Answer:
none of the above
Explanation:
The actual answer is '91 protons'. In fact, the beta decay of the thorium-234 is the following:

where inside the nucleus of Thorium (90 protons), a neutron turns into an electron (the beta particle) + a proton. Therefore, the resulting nucleus (which is Protoactinium) has a total of 90+1 = 91 protons.
So, the correct answer would be '91 protons'.
Answer:
(a) Yes, it is possible by raising the object to a greater height without acceleration.
Explanation:
The work-energy theorem states that work done on an object is equal to the change in kinetic energy, and change in kinetic energy requires a change in velocity.
If kinetic energy will not change, then velocity will not change, this means that there will be constant velocity and an object with a constant velocity is not accelerating.
If the object is not accelerating (without acceleration) and it remains at the same height (change in height = 0, and mgh = 0).
Thus, for work to be done on the object, without changing the kinetic energy of the object, the object must be raised to a greater height without acceleration.
Correct option is " (a) Yes, it is possible by raising the object to a greater height without acceleration".