Answer:
See attached handwritten document for answer
Explanation:
The problem is most likely that the commutator brushes bounces as the motor shaft rotates.
<h3>What is a DC motor?</h3>
This is referred to a device which converts direct current electrical energy into mechanical energy.
if the commutator brushes bounces as the motor shaft rotates over different materials, the ticking sound is heard.
Read more about DC motor here brainly.com/question/15721280
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Answer:
5.11 kg
Explanation:
Hooke's law states that stress is directly proportional to strain. It can be represented by the equation:
F = -kx
Where x is the displacement of the spring’s end from its equilibrium position, F is the force applied to the spring, k is a constant known as spring constant.
At first a force (F) of 62 N i used to stretch a spring by 12 cm (x).
Substituting into Hooke's equation:
F = kx
k = F/x = 62 / 12 = 5.17 N/cm
The spring is then held vertically and an object. The object is acted by upon by acceleration due to gravity since it is vertically upward. Therefore the force created by the object F = mg where g = acceleration due to gravity = 9.8 m/s². It causes a stretch (x) of 9.7 cm
Therefore:
mg = 5.17 N/cm × 9.7 cm
9.81m = 50.117
m = 50.117 / 9.81 = 5.11 kg
Answer:
a. Big Bang Theory explains the beginning of the universe. The entire matter of the universe is believed to be concentrated in a single point. This point had infinite density. At time, t = 0, at the big bang, universe started expanding and cooling down. This theory is most widely accepted theory describing the beginning of the universe. It is not considered as hypothesis because of the evidences received by the scientists- detection of cosmic microwave background, red shift of the light received from the galaxies indicating that universe is expanding.
b. Cosmic Microwave background radiation is a faint radiation having average temperature of 3 K detected every where around from the sky. This is a residual radiation from 400,000 years after the beginning of the universe. The universe was very hot and dense at the beginning and thus, opaque. Hence, detection of the CMB has provided the evidence of Big bang theory.
c. Scientists have proposed three models of the universe:
1. closed universe- The universe has finite volume and curves around itself. The space-time has positive curvature.
2. open universe - The universe has infinite volume and has a negative curvature.
3. flat universe - The universe has zero curvature. It has infinite volume. The actual density of the universe is equal to the critical density of the universe. The expansion rate slows down over time. This is the most widely accepted model.