Explanation:
It is a branch of astronomy wherein measurements of the positions and movements of celestial bodies are precisely are made.
For the measurement, minute wobbling of the position of the body is detected. When the shift is detected periodically, the astronomers come to know that the star is orbited by a planet.
Also, basic data about the properties of the stars can be collected using this method.
The correct answer to the question is 130.4 N.
CALCULATION;
The mass of the bullet is given as m = 28 gram = 0. 028 kg.
The initial velocity of the bullet u = 55 m/s
The final velocity of the bullet v = 18 m/s.
The distance covered by the bullet through the sand bag s = 29 cm.
= 0.29 m
Let the acceleration of the bullet is a .
From equation of kinematics, we know that-

⇒ 


The negative sign is used due to the fact that force is opposing in nature. Its velocity is decreasing with time.
From Newton's second law of motion, we know that net force on a body is equal to the product of mass with acceleration.
Mathematically F = ma.
Hence, the frictional force exerted on the bullet is calculated as -
F = m × a
= 0.028 × (-4656.897) N
= -130.4 N [ANS]
Here, N ( newton) stands for the unit of force.
Answer:
Angle of reflection = 30°
Explanation:
One of the laws of reflection is that the angle of incidence is equal to the angle of reflection.
The angle at which the light strikes the mirror is called the angle of incidence while the angle at which the light gets reflected back is called angle of reflection.
In this case, the angle of incidence is 30 degrees. So, we can say that the angle of reflection is also equal to 30 degrees.
Answer:
1 . What happens when you drop the stone?
Depending on the weight from which the stone was dropped, the glass might well break
2 depending on the size and weight and shape on the stone the glass might well break
3 depending on the density on the stone the stone might when float on the water
Explanition :
GIVE ME BRAINLESS PLEASE !!
I might be wrong, but. The words seem to fit.
When a hypothesis is wrong, scientists often begin by revising the question after that, its common for scientists to redesign the experiment.