Answer:
Part a)

Part b)

Part c)

Part d)
from t = 0 to t = 4.9 s
so the reading of the scale will be same as that of weight of the block
Then its speed will reduce to zero in next 3.2 s
from t = 4.9 to t = 8.1 s
The reading of the scale will be less than the actual mass
Explanation:
Part a)
When elevator is ascending with constant speed then we will have



So it will read same as that of the mass

Part b)
When elevator is decending with constant speed then we will have



So it will read same as that of the mass

Part c)
When elevator is ascending with constant speed 39 m/s and acceleration 10 m/s/s then we will have



Reading is given as



Part d)
Here the speed of the elevator is constant initially
from t = 0 to t = 4.9 s
so the reading of the scale will be same as that of weight of the block
Then its speed will reduce to zero in next 3.2 s
from t = 4.9 to t = 8.1 s
The reading of the scale will be less than the actual mass
Answer:30 cm
Explanation:
Given
object distance 
focal length of concave mirror 
height of object 
Using mirror formula




and magnification is



So height of object is same as of object .
Position :image is formed at the spot where object is placed.
Answer: Option 5.
Decreases increases increases.
Explanation:
Electromagnetic spectrum refers to differences in frequencies, wavelengths and photon energies of electromagnetic radiation.
From the top of the list to the bottom i.e from radio waves, infrared waves, visible lights, ultraviolet radiation, gamma radiation, wavelengths decreases, the frequency increases as the photon energy increases.
The electromagnetic radiations : radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays have high-frequency and short wavelengths. Their wavelengths decrease. The photon energy is directly proportional to wave frequency.
W=2485.65 J ,work did the movers do friction force a 41.0- kg crate 10.3 m across a rough floor without acceleration
<h3>What is a basic friction force?</h3>
Two surfaces that come into contact and slide against one another produce a force known as frictional force. Several aspects that influence the frictional force include: The surface texture as well as the amount of force attracting them together have the most effects on these forces.
<h3>What outcomes does friction produce?</h3>
It generates heat, which is useful for warming our bodies or specific areas of any object. Power is also lost as a result. It makes noise during every operation. We are able to walk, run, dance, etc. due to friction.
To know more about friction force visit:
brainly.com/question/1389727
#SPJ4