Answer:
N = 648.55[N]
Explanation:
To solve this problem we must use Newton's second law which tells us that the sum of forces on a body is equal to the product of mass by acceleration.
∑F = m*a
where:
∑F = Forces applied [N]
m = mass = 73.2 [kg]
a = acceleration = 0.950 [m/s²]
Let's assume the direction of the upward forces as positive, just as if the movement of the box is upward the acceleration will be positive.
By performing a summation of forces on the vertical axis we obtain all the required forces and other magnitudes to be determined.

where:
g = gravity acceleration = 9.81 [m/s²]
N = normal force (or weight) measured by the scale = 83.4 [N]
Now replacing:
![-(73.2*9.81)+N=-73.2*0.950\\-718.092+N=-69.54\\N = -69.54+718.092\\N = 648.55[N]](https://tex.z-dn.net/?f=-%2873.2%2A9.81%29%2BN%3D-73.2%2A0.950%5C%5C-718.092%2BN%3D-69.54%5C%5CN%20%3D%20-69.54%2B718.092%5C%5CN%20%3D%20648.55%5BN%5D)
The acceleration has a negative sign, this means that the elevator is descending at that very moment.
Answer:
The value is
Explanation:
From the question we are told that
The amount of power delivered is 
The time taken is 
The wavelength is 
Generally the energy delivered is mathematically represented as

Where
is the Planck's constant with value 
c is the speed of light with value 
So

=> 
Answer:
i/f = i/o + i/i f = focal, o = object, i = image
1 / i = 1 / f - 1 / o = (o - f) / o f
i = o * f / ( o - f) image distance
i = 12.5 * 22 / (12.5 - 22) = -28.9 cm
Image is real
Image is 28.9 cm to left of lens
M = - i / o = = 28.9 / 12.5 = 2.3 magnification (convex lens)
Answer:
B. they must be intrinsically far more luminous than the brightest galaxies.
Explanation:
Quasar is famous for being an intergalactic object which is billions of years away from the earth yet can still be seen, unlike the other star body, unlike giant galaxies.
Hence, the fact that quasars can be detected from distances where even the biggest and most luminous galaxies cannot be seen means that "they must be intrinsically far more luminous than the brightest galaxies."
This condition, including other related evidence gotten in recent years concerning our galaxy, has shown that quasars are probably the central nuclei of very distant, very active galaxies.
Answer:
Friction can stop or slow down the motion of an object.
Explanation:
The slowing force of friction always acts in the direction opposite to the force causing the motion.