Answer:
Explanation:
Given that
Mass , m = 25 kg
We know that when body is in rest condition then static friction force act on the body and when body is in motion the kinetic friction force act on the body .That is why these two forces are given as follows
Static friction force ,fs= 165 N
Kinetic friction force ,fk = 127 N
If the body is moving with constant velocity ,it means that acceleration of that body is zero and all the forces are balanced.
Lets take coefficient of kinetic friction = μk
The kinetic friction is given as follows
fk = μk m g
Now by putting the values
127 = μk x 25 x 9.81
Therefore the value of coefficient of kinetic friction will be 0.51
Simple machines could be used to reduce effort or extend the ability of people to perform tasks beyond their normal capabilities.
Examples include pulley, lever, and incline plane
Answer:
A. speed = 7.14 Km/s
B. distance = 1820.7 Km
Explanation:
Given that: a = 14.0 m/
, t = 8.50 minutes.
But,
t = 8.50 = 8.50 x 60
= 510 seconds
A. By applying the first equation of motion, the speed of the shuttle at the end of 8.50 minutes can be determined by;
v = u + at
where: v is the final velocity, u is the initial velocity, a is the acceleration and t is the time.
u = 0
So that,
v = 14 x 510
= 7140 m/s
The speed of the shuttle at the end of 8.50 minute is 7.14 Km/s.
B. the distance traveled can be determined by applying second equation of motion.
s = ut + 
a
where: s is the distance, u is the initial velocity, a is the acceleration and t is the time.
u = 0
s = a
= x 14 x 
= 7 x 260100
= 1820700 m
The distance that the shuttle has traveled during the given time is 1820.7 Km.
Answer:
C. water is more dense and viscous
Explanation:
Rapid gas exchange can be accomplished more easily in air than in water because water is more dense and viscous.
Gases have the greatest ease of diffusion of their respective particles, as occurs in air, since their molecules have higher speeds and have more distance from each other than liquids.
The molecular diffusion rate in liquids is much less than in gases. The molecules of a liquid are very close (liquids are more dense and viscous) to each other compared to those of a gas, then the gas molecules hits with the molecules of the liquid with more frequency and this causes that the gas moves slower than in other gas (for example in air).
