<h2>
Answer:Stretched rubber band with an mass</h2>
Explanation:
Simple harmonic motion requires a restoring force.
Simple harmonic motion should be periodic.
Option A:
When a rubber band is stretched,the internal forces of the rubber band pulls the band inside.So,internal forces are the restoring forces in a rubber band.
The motion is periodic as well since the the rubber band makes to an fro motion expanding ans contracting.
So,this performs SHM.
Option B:
There is no restoring force and no periodicity.
So,this is not SHM.
Option C:
There is no restoring force and no periodicity.
So,this is not SHM.
Option D:
There is periodicity but no restoring force.
So,this is not SHM.
Torque is equal position vector times (r) times force vector
(F). Since F= 10 N and r = 0.1 m, so the
torque is equal to (10 N) x ( 0.1 m) = 1Nm. The direction of the torque would
be into the screen, clockwise rotation.
Answer:

Explanation:
The resistance is given as

Where A IS Cross sectional area of wire
therefore resistivity \rho can be wrtten as

Putting all value to get resistivity value

Main sequence stars are characterised by the source of their energy.They are all undergoing fusion of hydrogen into helium within their cores. The mass of the star is the main element for such process or phenomenon to take place for it is a determinant of both the rate at which they perform the said activity and the amount of fuel available.
To answer the question, the lower mass limit for a main sequence star is about 0.08. If the mass of a main sequence star is lower than the above-mentioned value, there would be a deficit or insufficiency of gravitational force to generate a standard temperature for hydrogen core fusion to take place and the underdeveloped star would form into a brown dwarf instead.