B is correct answer.
The atomic mass is the most important because it tells you the number of electrons.
Hope it helped you.
-Charlie
Answer:
For the first situation, we first need to find the mass of the second train car.
In order to do that, we apply the conservation of the amount of movement:

and we have as a result:
m2 = 289.6875
For the second situation, also we will apply the conservation of the amount of movement:

and we have as a result:
V = 2.64 (it is moving to the right)
Based on how they each acted in the trials, the substance that would be the most metallic is B.
Answer:
0.82 m
Explanation:
We are given that
Weight,
=225 N
Length,l=5 m
d=1.1 m
We have to find the distance x for which person weighs 385 N walk on the overhanging part of the plank before it just begins to tip.
Half length=


When system in equilibrium then




Answer:
Weight of the object will be 195.6 N
Explanation:
We have given mass of the object m = 20 kg
And acceleration due to gravity at any location is given 
We have to find the weight of the object in N at the location where value of acceleration due to gravity is 
Weight of the object is given by W = mg , here W is weight , m is mass and g is acceleration due to gravity
So weight W = 20×9.78 = 195.6 N
So weight of the object will be 195.6 N