What is the most likely reason that Mendeleev placed tellurium before iodine?
1 answer:
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Answer:
Explanation:
Use the one-dimensional equation
which says that the final velocity of an object is equal to the object's initial velocity plus its acceleration times time. We are looking for time. That means the equation looks like this:
0 = 30 + (-4)t and
-30 = -4t so
t = 7.5 sec
Answer:
See below ↓
Explanation:
<u>Step 1 : Diagram</u>
- In attachment
<u>Step 2</u>
- We choose the system to be the spring, the block, and the Earth and it is isolated
- We put all the data in the figure we have created and create a zero level (initial height) of the block to be yₓ = 0 and the final position, when it stops and moves upwards again, to be yₙ = -A
- No external forces are exerted on the system and no energy comes in or out of the system
- Hence,
⇒ ΔE = 0
⇒ Eₙ - Eₓ = 0
⇒ Eₙ = Eₓ
⇒ Kₙ + Uₙ + Pₙ = Kₓ + Uₓ + Pₓ
- Final kinetic energy is 0 at the lowest point
⇒ Uₙ + Pₙ = Uₓ + Pₓ
<u>Step 3</u>
- Initial potential energy is 0 [zero level = initial height]
⇒ Uₙ + Pₙ = Uₓ
- And we know that spring was originally at normal length, so initial spring energy is also 0
⇒ Uₙ + Pₙ = 0
⇒ 1/2kxₙ² + mgyₙ = 0
⇒ 1/2kxₙ² = -mgyₙ
- We know xₙ = A and yₙ = -A from the diagram
⇒ 1/2kA² = -mg(-A)
⇒ 1/2kA² = mgA
⇒ [1/2kA = mg]
<u>Step 4</u>
- Spring force is given by : F = -kx
- Note : x = A
⇒ F = kA
⇒ k = F/A
⇒ Plug 'k' into the equation found at the end of Step 3
⇒ 1/2(F/A)(A) = mg
⇒ 2F = mg
⇒ F = 2mg (a)
<u>Step 5</u>
- We know the spring will stop oscillating and be at rest at the new equilibrium position of the system
⇒ F - mg = 0
⇒ F = mg
- We know that :
⇒ F = -kx
- In the case x = yₙ
⇒ kyₙ = mg
⇒ yₙ = mg/k
⇒ yₙ = 0.25 x 9.8 / -10
⇒ yₙ = -0.245 m
⇒ yₙ = A
⇒ yₙ = 0.245 m (b)
<u>Step 6</u>
- v(max) = Aω
- v(max) = A√k/m
- v(max) = 0.245 x √(10/0.25)
- v(max) = 1.55 m/s (c)
