Answer:
U₂ = 20 J
KE₂ = 40 J
v= 12.64 m/s
Explanation:
Given that
H= 12 m
m = 0.5 kg
h= 4 m
The potential energy at position 1
U₁ = m g H
U₁ = 0.5 x 10 x 12 ( take g= 10 m/s²)
U₁ = 60 J
The potential energy at position 2
U₂ = m g h
U ₂= 0.5 x 10 x 4 ( take g= 10 m/s²)
U₂ = 20 J
The kinetic energy at position 1
KE= 0
The kinetic energy at position 2
KE= 1/2 m V²
From energy conservation
U₁+KE₁=U₂+KE₂
By putting the values
60 - 20 = KE₂
KE₂ = 40 J
lets take final velocity is v m/s
KE₂= 1/2 m v²
By putting the values
40 = 1/2 x 0.5 x v²
160 = v²
v= 12.64 m/s
Physical changes: breaking sticks, boiling the water
chemical changes: lighting the fire
(Breaking the wood does not change the substance of the wood , therefore it's a physical change. Water changing between solid, liquid, and gas form is always a physical change.)
Answer:
If the speed of the merry-go-round doubles, the force you will need to exert to hang on is 400 N.
Explanation:
Given;
initial force exerted to hang on, F₁ = 100 N
The force exerted on the merry-go-round in order to hang on must be an inward force known as centripetal force.
Centripetal force is given by;
Therefore, If the speed of the merry-go-round doubles, the force you will need to exert to hang on is 400 N.
Index fossils are used to determine the relative ages of rock and fossils and are also used to define the boundaries between geologic periods.
<u>Option: A</u>
<u>Explanation:</u>
The fossils which are recognized as fossils guides or indicator fossils are used to classify and recognize geological or faunal periods, termed as index fossils. It must be of short vertical reach, wide geographic distribution and swift patterns in evolution. It helps to assess the rock layers ' age and helps to date other fossils found close and around them. For an instance, Ammonites were abundant in the Mesozoic period between 245 to 65 mya, they have not been found after the Cretaceous era, as they became endangered during the K-T extinction (65 mya).
The self-inductance of the solenoid is 8.25 mH.
The given parameters;
- <em>number of turns, N = 1700 turn</em>
- <em>length of the solenoid, l = 55 cm = 0.55 m</em>
- <em>diameter of solenoid, d = 4 cm</em>
- <em>radius of the solenoid, r = 2 cm = 0.02 m</em>
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The area of the solenoid is calculated as follows;
The self-inductance of the solenoid is calculated as follows;
Thus, the self-inductance of the solenoid is 8.25 mH.
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