The derivative of the function space as a function of time is equal to a function of speed as a function of time.
The velocity vector is given by the vector sum of the velocities of both axes.

If you notice any mistake in my english, please let me know, because I am not native.
Answer:

Explanation:
As we know that tank itself has mass given as 13.4 kg
so it is given as

also the tank contains air in it and the mass of air inside the tank is also given as 4.47 kg
so it is

so total mass of the tank is the mass of the empty tank and mass of air in the tank



Answer:
The magnitude of the electrostatic force is 120.85 N
Explanation:
We can use Coulomb's law to find the electrostatic force between the down quarks.
In scalar form, Coulomb's law states that for charges
and
separated by a distance d, the magnitude of the electrostatic force F between them is:

where
is Coulomb's constant.
Taking the values:


and knowing the value of the Coulomb's constant:

Taking all this in consideration:


Answer:
(a) 
(b) 
Explanation:
The average power is defined as the amount of work done during a time interval:

According to work-energy theorem, the work done is equal to the change in kinetic energy. So, we have:

Recall that the weight is given by:

The car accelerates uniformly from rest (
). Replacing (3) in (2), we have:

(a) Finally, we replace this in (1):

(b)

Answer:
50 Km
Explanation:
If the car moved 50 km north and then 50 south its displacement would be 0. if it go in a direction like sw or ne or nw