Answer:
The objective lens is an optical tool used to focus an image.
Explanation:
The objective lens is an optical tool that collects light emitted by an object under observation and focuses the rays of light in order to form a real and magnified image They are used in optical instruments like microscopes, cameras, telescopes, etc. and are also referred as objective or object glasses.
Answer:
v = 3.08 km/s
Explanation:
Given that,
The angular velocity of the satellite = 
A satellite is in orbit 36000km above the surface of the earth.
The radius of the earth is 6400 km
Let v is the velocity of the satellite. It can be calculated as :

So, the velocity of the satellite is 3.08 km/s.
Incomplete question as the unit of volume is not written correctly.So the complete question is here:
A straightforward method of finding the density of an object is to measure its mass and then measure its volume by submerging it in a graduated cylinder. What is the density of a 240-g rock that displaces 89.0 cm³?
Answer:

Explanation:
Given data
Mass m=240g
Volume V=89.0 cm³
To find
Density d
Solution
If rock displaces 89.0 cm³ of water means volume of rock is also 89cm³
So

<span>Like most Earth materials, rocks are created and destroyed in cycles. The rock cycle is a model that describes the formation, breakdown, and reformation of a rock as a result of sedimentary, igneous, and metamorphic processes. </span><span>All rocks are made up of minerals. A mineral is defined as a naturally occurring, crystalline solid of definite chemical composition and a characteristic crystal structure. A rock is any naturally formed, nonliving, firm, and coherent aggregate mass of solid matter that constitutes part of a planet. i don't know if this is right but i hope it helps</span>