Chemistry for Biologists: Some basic chemistry
Some basic chemistry
Living organisms and chemistry
Biology is about living things - organisms. All living organisms are made of chemicals. To understand biological substances and the changes that take place in living organisms you need a good knowledge of the underlying chemistry. We will build up a picture of the chemicals that make up living organisms by starting small and getting bigger.
The starting point is atoms - the building blocks of all matter. We will then look at how these come together to make elements and compounds.
I believe the correct answer is atmosphere (D).
The vector sum is the algebraic sum if the two vectors have the same direction.
The sum vector is zero if the two vectors have the same magnitude and opposite direction
Vector addition is a process that can be performed graphically using the parallelogram method, see attached, where the second vector is placed at the tip of the first and the vector sum goes from the origin of the first vector to the tip of the second.
There are two special cases where the vector sum can be reduced to the algebraic sum if the vectors are parallel
case 1. if the two vectors are parallel, the sum vector has the magnitude of the sum of the magnitudes of each vector
case 2. If the two vectors are antiparallel and the magnitude of the two vectors is the same, the sum gives zero.
In summary in the sum of vectors If the vectors are parallel it is reduced to the algebraic sum, also in the case of equal magnitude and opposite direction the sum is the null vector
Answer:
Recoil speed,
Explanation:
Given that,
Mass of the comet fragment, 
Speed of the comet fragment, 
Mass of Callisto, 
The collision is completely inelastic. Assuming for this calculation that Callisto's initial momentum is zero. So,

V is recoil speed of Callisto immediately after the collision.

So, the recoil speed of Callisto immediately after the collision is 
Answer:
32.5 ms⁻¹
Explanation:
<em><u>Theory
</u></em>
<u>
The law of conservation of linear momentum
</u>
The sum of linear momentum of a system under no external force remains constant.
In this scenario although different forces act on two vehicles by each other when we consider the total system of two cars no external unbalance force act on them. So we can apply this law.
As law says,
The sum of linear momentum before collision = The sum of linear momentum after collision.
Momentum = mass × velocity
1000×40+3000×35 = 1000×v + 3000×37.5
where v = velocity of the red car after the cash
v = 32.5 ms⁻¹