It’s gonna be Oxygen ....
Friction is the force you get when you (for example) Rub something with another, it's a force that may generate heat and even some resistance. Another example is rubbing your hands together, they get hot, therefore friction is working, without friction you wouldn't be able to stop moving.
Answer:
Explanation: When a body covers unequal distances in equal intervals of time in a specified direction, the body is said to be moving with a variable velocity. Example: A rotating fan at a constant speed has variable velocity, because of continuous change in direction.
Answer:
The taken is 
Explanation:
Frm the question we are told that
The speed of car A is 
The speed of car B is 
The distance of car B from A is 
The acceleration of car A is 
For A to overtake B
The distance traveled by car B = The distance traveled by car A - 300m
Now the this distance traveled by car B before it is overtaken by A is

Where
is the time taken by car B
Now this can also be represented as using equation of motion as

Now substituting values

Equating the both d

substituting values




Solving this using quadratic formula we have that

Answer:
The final acceleration becomes (1/3) of the initial acceleration.
Explanation:
The second law of motion gives the relationship between the net force, mass and the acceleration of an object. It is given by :

m = mass
a = acceleration
According to given condition, if the mass of a sliding block is tripled while a constant net force is applied. We need to find how much does the acceleration decrease.

Let a' is the final acceleration,

m' = 3m



So, the final acceleration becomes (1/3) of the initial acceleration. Hence, this is the required solution.