I don't know the exact answer but I know it is NOT D or C, I am shooting for A but I may be wrong. A
To develop this problem we will apply the concepts related to Sound Intensity. This can be defined as the power carried by sound waves per unit area in a direction perpendicular to that area. Mathematically it can be written as,
= Level Difference
n = Number of equal loud sound sources
n = 15
Therefore replacing we have,
Therefore over 100dB the total difference intensity level would be
Here,
The intensity level generated by one engine is
Gasoline comes from petroleum, which is a fossil fuel. Petroleum, coal and natural gas (methane) are all made in the earth's crust from the bodies of plants and animals that died long ago. That's why they are called fossil fuels.
The sun provides the energy that all life needs to grow and reproduce. Therefore, fossil fuels can be considered a form of solar energy that has been stored in the bodies of living things, and then concentrated in hydrocarbon deposits in the earth's crust.
The fact is that all the energy on earth comes from the sun, directly or indirectly, except for nuclear energy, which comes from radioactive elements that were made in other stars that existed before the sun.
Hope this helps!!!
Answer: a. 667N
b. 665N
c. 54.5N
Explanation:
a) on the surface of the earth
W = mg
W = 68 × 9.81
= 667N
b) at the top of Everest (8848 m above sea level).
W =mg × R²/(R + H)²
W = 667 × [6378²/(6378 + 8.848)²
W = 665N
c) has 2 1/2 times the radius of the earth
W = mg × R²/(R + H)²
W = 667 × R²/(R + 2.5R)²
W = 54.5N
Answer: X = 52,314.12 N
Explanation: Let X be the force the feet of the athlete exerts on the floor.
According to newton's third law of motion the floor gives an upward reaction based on the weight of the athlete and the barbell which is known as the normal reaction ( based on the mass of the athlete and the barbell)
Mass of athlete = 87kg, mass of barbell = 600/ hence total normal reaction from the floor = 87* 61.22/ 9.8 *9.8 = 52,200N.
The athlete lifts the barbell from rest thus making it initial velocity u=0, distance covered = S = 0.65m and the time taken = 1.3s
The acceleration of the barbell is gotten by using the equation of constant acceleration motion
S= ut + 1/2at²
But u = 0
S = 1/2at²
0.65 = 1/2 *a (1.3)²
0.65 = 1.69 * a/2
0.65 * 2 = 1.69 * a
a = 0.65 * 2/ 1.69
a = 0.77m/s²
According to newton's second law of motion
Resultant force = mass * acceleration
And resultant force in this case is
X - 52,200 = (87 + 61.22) * 0.77
X - 52,200 = 148.22 * 0.77
X - 52, 200 = 114.132
X = 114.132 + 52,200
X = 52,314.12 N
