Answer:
As Per Given Information
20x objective lens was used by specimen
10x ocular lens was also used by him.
we have to find the total magnification.
For calculating the total magnification we 'll simply do multiplication
Total Magnification = 20x × 10x
Total Magnification = 200x
So , the total magnification will be 200x .
Answer: acceleration due to gravity of planet a would be twice that of planet b. Given that the radius are thesame.
Explanation:
Acceleration due to gravity is as a result of the gravitational force of attraction of a planet to its centre.
g = GM/r^2
Where;
g = acceleration due to gravity
G = gravitational constant
M = mass of planet
r = radius of planet
Given that the two planet have the same radius, if the mass of planet a is twice the mass of planet b the the acceleration due to gravity of planet a would be twice that of planet b, because acceleration due to gravity is directly proportional to the mass of the planet.
I believe the answer is A
Answer:
v = -1.8t+36
20 seconds
360 m
40 seconds
36 m/s
The object speed will increase when it is coming down from its highest height.
Explanation:

Differentiating with respect to time we get

a) Velocity of the object after t seconds is v = -1.8t+36
At the highest point v will be 0

b) The object will reach the highest point after 20 seconds

c) Highest point the object will reach is 360 m


d) Time taken to strike the ground would be 20+20 = 40 seconds
![[tex]v=u+at\\\Rightarrow v=0+0.9\times 2\times 20\\\Rightarrow v=36\ m/s](https://tex.z-dn.net/?f=%5Btex%5Dv%3Du%2Bat%5C%5C%5CRightarrow%20v%3D0%2B0.9%5Ctimes%202%5Ctimes%2020%5C%5C%5CRightarrow%20v%3D36%5C%20m%2Fs)
Acceleration will be taken as positive because the object is going down. Hence, the sign changes. 2 is multiplied because the expression is given in the form of 
e) The velocity with which the object strikes the ground will be 36 m/s
f) The speed will increase when the object has gone up and for 20 seconds and falls down for 20 seconds. The object speed will increase when it is coming down from its highest height.
Answer:
The angular speed of the system increases.
The moment of inertia of the system decreases.
Explanation:
As we know that the girl is going towards the center of the circle so here the moment of inertia of the girl is given as

here we know that
r = position of the girl from the center of the disc
now we know that the girl is moving towards the center so its distance will continuously decreasing
So the moment of inertia of the girl will decrease
Now we know that that with respect to the center of the disc there is no torque on the disc + girl system
So here we can use angular momentum conservation
So we have

since moment of inertia is decreasing for the system
so angular speed will increase