Answer:
To find out what water is made of, it helps to look at its chemical formula, which is H2O. This basically tells us that the water molecule is composed of two elements: hydrogen and oxygen or, more precisely, two hydrogen atoms (H2) and one oxygen atom (O).
Explanation:
Answer:
2m/s^2
Explanation:
Clculate the acceleration:
V = u +at
20m/s = 0 + a*10s
a = 20m//10s
a = 2m/s²
From the data given , it is not possible to calculate the displacement , because no direction of motion is given
But it is possible to calculate the distance travelled
Distance = ut + ½ *a*t²
distance = 0 + ½ * 2m/s * 10²s
distance = 100m
Answer:

Explanation:
Diffraction is observed when a wave is distorted by an obstacle whose dimensions are comparable to the wavelength. The simplest case corresponds to the Fraunhofer diffraction, in which the obstacle is a long, narrow slit, so we can ignore the effects of extremes.
This is a simple case, in which we can use the Fraunhofer single slit diffraction equation:

Where:

Solving for λ:

Replacing the data provided by the problem:

Answer:
The acceleration of the car will be 
Explanation:
We have given that distance from stop sign s = 200 m
Time t = 0.2 sec
We have to find the constant acceleration
Now from second equation of motion 


So the acceleration of the car will be 
Answer:
(B) Dark energy does not exist and there is much more matter than current evidence suggests.
Explanation:
The repulsive force which is accelerating expansion of the universe is called as dark energy. Most of matter present in the universe is the dark matter of about eighty five percent.
So, a collapsing universe would not have the dark energy and there is more matter which is not the dark matter. This theory is rejected because expansion of the universe is observable.