The concepts used to solve this problem are those related to the Pythagorean theorem for which we will calculate the distance and the pitch.
According to the attached diagram we have that the expression of the resulting displacement is

Therefore the resultant displacement of the girl is



Therefore the girl has displaced around of 5 blocks
We will solve this question using the second law of motion which states that force is directly equal to the product of mass and acceleration.

Where,
- F is force
- m is mass
- a is acceleration
In our case,
- F = ?
- m = 2500 kg
- a = 20m/s

<em>Thus, The force of 50000 Newton is required to accelerate a car of 2500 kg...~</em>
Answer:

Explanation:
Given that,
The speed of an electromagnetic wave traveling in a transparent nonmagnetic substance is given by :

Where
k is the dielectric constant of the substance.
v is the speed of light in water


So, the speed of light in water is 
Answer:
5 Km/h
Explanation:
From the question given above, the following data were obtained:
Distance travelled = 10 Km
Time = 2 hours
Speed =?
Speed is simply defined as the distance travelled per unit time. Mathematically, it can be represented as:
Speed = distance travelled /time.
With the above formula, we can obtain the speed at which the duck is travelling as follow:
Distance travelled = 10 Km
Time = 2 hours
Speed =?
Speed = distance travelled /time.
Speed = 10 / 2
Speed = 5 Km/h
Thus, the duck is travelling at a speed of 5 Km/h