Answer: v = 
Explanation: q = magnitude of electronic charge = 
mass of an electronic charge =
V= potential difference = 4V
v = velocity of electron
by using the work- energy theorem which states that the kinetic energy of the the electron must equal the work done use in accelerating the electron.
kinetic energy =
, potential energy = qV
hence, 

The inner planets are rocky because The warm temperatures in the inner disk caused the inner planetesimals to be formed of mostly rocky material.
What are rocky planets?
- Rocky planets are the planet in which constituents are mostly silicate rocks or metal. They are also regarded as a planet with a solid surface.
- The formation of rocky planets is said to have occurred billions of years ago and its process of formation is termed accretion. Through accretion are its constituents formed as the more it goes bigger, the higher the rising temperature and pressure in its core and the elements which have to undergo accreted heat up, melt, and spread. Through this process, heavier elements go deeper into the core of the planet and lighter elements float toward the surface.
- In the formation of rocky planets, the inner portions of the disk are said to be warm from the protostar thereby resulting in the production of the heavy elements that stay there.
- Examples of rocky planets are Earth or Mars
Hence, from the above, we can say that,
The warm temperatures in the inner disk caused the inner planetesimals to be formed of mostly rocky material.
Here,
Option A is correct.
Learn more about rocky planets here:
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Solution :
Given :
M = 0.35 kg

Total mechanical energy = constant
or 
But
and 
Therefore, potential energy at the top = kinetic energy at the bottom


(h = 35 cm = 0.35 m)
= 2.62 m/s
It is the velocity of M just before collision of 'm' at the bottom.
We know that in elastic collision velocity after collision is given by :

here, 
∴ 

= 0.33 m/s
Therefore, velocity after the collision of mass M = 0.33 m/s
The net force of the object is equal to the force applied minus the force of friction.
Fnet = ma = F - Ff
12 kg x 0.2 m/s² = 15 N - Ff
The value of Ff is 12.6 N. This force is equal to the product of the normal force which is equal to the weight in horizontal surface and the coefficient of friction.
Ff = 12.6 N = k(12 kg)(9.81 m/s²)
The value of k is equal to 0.107.
If<span> The </span>Sun<span> Went Out, How Long </span>Could<span> Life On </span>Earth<span> Survive? ... (which is actually physically impossible), the </span>Earth would stay<span> warm—at least ... from the planet's core </span>would<span> equal the</span>heat<span> that the </span>Earth<span> radiates into space, ... Photosynthesis </span>would<span> halt immediately, and </span>most<span> plants</span>would<span> die </span>in<span> a few </span>weeks<span>.</span>