Class 11th
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New answer posted
2 months ago
Contributor-Level 10
v? ²/2 + P? /ρ + gh? = v? ²/2 + P? /ρ + gh?
⇒ v? ²/2 + (P? + ρgh + mg/A)/ρ + g * 0 = v? ²/2 + P? /ρ + g * 0
⇒ v? ²/2 + (ρgh + mg/A)/ρ = v? ²/2 . (1)
Using Continuity equation, we can write
Av? = av? ⇒ v? = (a/A)v?
Putting the value of v? in equation (1), we have
(a²/A²)v? ²/2 + (ρgh + mg/A)/ρ = v? ²/2 ⇒ (A² - a²)/A² * v? ²/2 = (ρgh + mg/A)/ρ
⇒ v? = √ [ (A²/ (A²-a²) * 2 (ρgh + mg/A)/ρ] = 3.09 m/s ≈ 3 m/s
New answer posted
2 months agoContributor-Level 9
Be is used in X ray tube windows.
Mg is used in incendiary bombs & signals.
Compounds of Ca i.e CaCO? is used in extraction of metals like Fe.
Radium (Ra) is used in treatment of cancer in radiotherapy.
New answer posted
2 months agoContributor-Level 10
v_rms = √ (3RT/M) and v_av = √ (8RT/πM)
⇒ v_rms / v_av = √ [ (3RT/M) / (8RT/πM)] = √ (3π/8)
New answer posted
2 months ago
Contributor-Level 10
μ_min = (I tanθ)/ (I + mR²)
= [ (mR²/2)tanθ] / [mR²/2 + mR²] = (tanθ)/3 = (tan 60°)/3 = √3/3 = 1.732/3 = 0.5773
Since given coefficient of static friction is less than μ_min, so body will perform rolling with slipping and kinetic friction will act
F? = μN = μmg cosθ = (0.4) * mg cos 60° = mg/5
New answer posted
2 months agoContributor-Level 10
Let x = m(a + λb).
Given m(a + λb) ⋅ (3i + 2j - k) = 0, which leads to λ = -3/8.
The projection of vector x on vector a is given by x ⋅ â, where â is the unit vector of a.
Projection = (x ⋅ a) / |a| = 17√6 / 2
x ⋅ a = (m(a + λb)) ⋅ a = m(a ⋅ a + λ(b ⋅ a)) = m(|a|^2 + λ(b ⋅ a))
The provided text simplifies this to:
m(6 - 3/8 * (-1)) = 17√6 / 2
m * (51/8) = 17 * 6 / 2 (The text seems to have a typo 17x6/2 instead of 17√6 / 2)
Assuming it is 17 * 6 / 2, m * 51/8 = 51, so m = 8.
x = 8(a + (-3/8)b) = 8a - 3b
x = 8( (13/8)i - (14/8)j + (11/8)k ) (The vectors a and b are not fully defined in the provided text)
The final vec
New answer posted
2 months agoContributor-Level 10
If the orthocenter and circumcenter of a triangle both lie on the y-axis, the centroid also lies on the y-axis.
The x-coordinate of the centroid is (x1 + x2 + x3) / 3. If the vertices are (cos α, sin α), (cos β, sin β), (cos γ, sin γ), then the x-coordinate of the centroid is (cos α + cos β + cos γ) / 3.
Since the centroid lies on the y-axis, its x-coordinate is 0.
cos α + cos β + cos γ = 0
Using the identity: If a + b + c = 0, then a^3 + b^3 + c^3 = 3abc.
Let a = cos α, b = cos β, c = cos γ.
Then, cos^3 α + cos^3 β + cos^3 γ = 3 * cos α * cos β * cos γ.
We need to evaluate the expression:
(cos 3α + cos 3β + cos 3γ) / (
New question posted
2 months agoNew answer posted
2 months agoContributor-Level 10
With the help of definition of e, we can write
e = v? /v? = 2v/u ⇒ u = 2v/e . (2)
Putting the value of e in equation (1), we have
m? (2v/e) = (m? - m? )v ⇒ 2m? = em? - em? ⇒ m? /m? = (2+e)/e = 1 + 2/e > 2
New answer posted
2 months agoContributor-Level 9
Bohr's theory accounts for the line spectrum of single electron species but Li? has two electrons. Bohr's theory fails to explain splitting of spectral lines in presence of magnetic field i.e. Zeeman effect.
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