इन्जिनियरिङ प्रवेश – Mathematics, Physics, Chemistry, English
इन्जिनियरिङ प्रवेश – Mathematics, Physics, Chemistry, English
Engineering Entrance – Mathematics, Physics, Chemistry & English · ३,८४१ प्रश्न
३,८४१ प्रश्न उपलब्ध। मोड छान्नुहोस्:
इन्जिनियरिङ प्रवेश: प्रश्न र उत्तर
सही लागेको विकल्पमा थिच्नुहोस्। सही भए हरियो, गलत भए रातो देखिन्छ; ३ सेकेन्डपछि सही उत्तर र व्याख्या देखिन्छ।
सही: ० / ०
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Because of the Earth's rotation, the effective value of g at the equator is less than it would be without rotation by about (R = 6400 km):
सही उत्तर: ग) 0.034 m/s²
The reduction is ω²R = (7.27 × 10⁻⁵)² × 6.4 × 10⁶ ≈ 0.034 m/s².
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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For a wheel rolling without slipping with centre speed v, the speed of the topmost point relative to the ground is:
सही उत्तर: क) 2v
The top point has translational velocity v plus rotational velocity ωR = v in the same direction, giving 2v.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A thin uniform rod of length L stands vertically on a frictionless pivot at its lower end and falls over. The speed of its upper end just before it hits the floor is:
सही उत्तर: क) √(3gL)
Loss of PE mgL/2 = ½(mL²/3)ω², so ω = √(3g/L) and the tip speed is ωL = √(3gL).
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A solid sphere rolling without slipping on a level floor with speed v reaches the foot of an incline and rolls up it. The greatest height it reaches is:
सही उत्तर: घ) 7v²/(10g)
Total KE = ½mv²(1 + 2/5) = 7mv²/10 = mgh, so h = 7v²/(10g).
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The moment of inertia of a uniform rectangular plate of mass M and sides a and b about an axis through its centre perpendicular to its plane is:
सही उत्तर: ख) M(a² + b²)/12
Using the perpendicular axis theorem: I = Ma²/12 + Mb²/12 = M(a² + b²)/12.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The moment of inertia of a thin uniform square plate of mass M and side a about one of its diagonals is:
सही उत्तर: ख) Ma²/12
By the perpendicular axis theorem the two diagonals share I_z = Ma²/6 equally, so I_diagonal = Ma²/12.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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In a 'rotor' ride, people stand against the wall of a vertical cylinder of radius 2 m with μ = 0.5 between them and the wall. The floor can be removed safely once the angular speed reaches at least (g = 10 m/s²):
सही उत्तर: ग) about 3.2 rad/s
Friction μN = μmω²r must balance mg, so ω = √(g/(μr)) = √(10/1) ≈ 3.2 rad/s.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A 1000 kg car crosses the bottom of a dip (concave road) of radius 20 m at 10 m/s. The normal force on the car at the lowest point is (g = 10 m/s²):
सही उत्तर: ग) 15000 N
N − mg = mv²/r, so N = 1000(10 + 100/20) = 15000 N.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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A ball dropped from a height of 10 m keeps bouncing on a floor with coefficient of restitution 0.5. The total distance it travels before coming to rest is about:
सही उत्तर: ख) 16.7 m
Each rebound height is e² times the previous, so the total distance = h(1 + e²)/(1 − e²) = 10 × 1.25/0.75 ≈ 16.7 m.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The potential energy of a particle moving along the x-axis is U = x³ − 3x (SI units). A position of stable equilibrium is:
सही उत्तर: घ) x = 1 m
dU/dx = 3x² − 3 = 0 at x = ±1; d²U/dx² = 6x is positive at x = 1 (minimum of U), so x = 1 m is stable.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
यी अभ्यास प्रश्न हुन्, आधिकारिक प्रश्न होइनन्। पाठ्यक्रम, विज्ञापन र नतिजाका लागि सम्बन्धित निकायको आधिकारिक वेबसाइट हेर्नुहोस्। उत्तरमा गल्ती भेटे प्रश्नमुनिको "टिप्पणी / गल्ती रिपोर्ट" मा लेख्नुहोस्।
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