Answer:
physical health
Explanation:
Physical health has many components including: exercise, nutrition, sleep, alcohol & drugs, and weight management.
Answer:
Is always towards the center of the Earth
Explanation:
As a satellite moves around the Earth in a circular orbit, the direction of the force of gravity is always towards the center of the Earth. At an altitude of 100 km, you would be so high that you would see black sky and stars if you looked upwards.
Answer:
B.) by interfering with sound waves
Explanation:
As we know that the interference of sound waves is of two types
1). constructive interference
2). destructive interference
now we know that constructive interference means the resultant intensity will be more than the intensity of interfering waves as here two waves are in same phase.
In destructive interference the resultant of two waves is given by the minimum resultant of the intensity as here the phase of two waves are opposite to each other.
So we will say that

here in case of noise cancelling headphones we know that the phase of noise is always made in opposite phase with the sound which is used to cancelled the noise.
This will reduce the noise and we will get a clear sound
Given :
The ball of a ballpoint pen is 0.5 mm in diameter and has an ASTM grain size of 12.
To Find :
How many grains are there in the ball?
Solution :
Volume of ball of the ballpoint is :

Now, grain size of 12 has about 520000 grains/mm³.
Therefore, number of grains are :

To find out the kinetic friction, using the coefficient friction formula.
What is kinetic friction?
A force that acts between moving surfaces is called "kinetic friction." A force acting in opposition to the direction of a moving body on the surface is felt. The two materials' kinetic friction coefficients will determine how much force is applied.
What is coefficient friction?
A measure of the degree of friction between two surfaces is the coefficient of friction. A coefficient of friction is determined by calculating the resistance to motion at the intersection of two surfaces made of the same or different materials.
UK
U-coefficient of friction
K-Kinetic friction
Using UK
450+370-f=m*o
f=820=UK*260*9.8
UK=2.548
820/2.548
UK= 321.8210361
Therefore the coefficient of kinetic friction is 321.8210361
Learn more about Kinetic friction from the given link.
brainly.com/question/14111192
#SPJ4