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A light string passing over a smooth light fixed pulley connects two blocks of masses m_1 and m_2. If the acceleration of the system is g/8, then the ratio of masses is
Pulley Systems and Tension diagram for Q31 - JEE Main 2024 Evening
The image displays two masses suspended over a single fixed smooth pulley.

Solution & Explanation

### Related Formula a = frac(m_1 - m_2)g(m_1 + m_2) ### Core Logic Assuming m_1 > m_2, the net pulling force is (m_1 - m_2)g and the total mass to be accelerated is (m_1 + m_2). Given that the acceleration of the system is a = fracg8. ### Step 1: Algebraic Manipulation fracg8 = frac(m_1 - m_2)g(m_1 + m_2) m_1 + m_2 = 8m_1 - 8m_2 8m_2 + m_2 = 8m_1 - m_1 9m_2 = 7m_1 fracm_1m_2 = frac97 ### Pattern Recognition For standard Atwood machines, a = g times fractextDifference in masstextSum of mass. If a/g = 1/8, then (m_1-m_2)/(m_1+m_2) = 1/8, which can be solved using componendo and dividendo: m_1/m_2 = (8+1)/(8-1) = 9/7. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Physics: Laws of Motion

Reference Study Guides

More Laws of Motion Previous-Year Questions — Page 3

Q37 jee_main_2024_01_february_morning Circular Motion
A ball of mass 0.5mathrm~kg is attached to a string of length 50mathrm~cm. The ball is rotated on a horizontal circular path about its vertical axis. The maximum tension that the string can bear is 400mathrm~N. The maximum possible value of angular velocity of the ball in mathrmrad/s is:
  • A. 1600
  • B. 40
  • C. 1000
  • D. 20

Solution

### Related Formula Centripetal force configuration for simplified horizontal rotation layout: T = momega^2 l ### Core Logic Given values: m = 0.5mathrm~kg, l = 50mathrm~cm = 0.5mathrm~m, T_textmax = 400mathrm~N. Equating max tension to centripetal requirement: 400 = 0.5 times omega^2 times 0.5 ### Step 1: Compute Angular Velocity 400 = 0.25 omega^2 omega^2 = frac4000.25 = 1600 omega = sqrt1600 = 40mathrm~rad/s ### Pattern Recognition Ensure units are metric (50mathrm~cm to 0.5mathrm~m). Direct mapping to horizontal string projection metrics. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Physics: Laws of Motion
Q48 jee_main_2024_01_february_morning Friction
Consider a block and trolley system as shown in figure. If the coefficient of kinetic friction between the trolley and the surface is 0.04, the acceleration of the system in mathrmms^-2 is (Consider that the string is massless and unstretchable and the pulley is also massless and frictionless):
Block and trolley tension system for Q48 - JEE Main 2024 Morning
A block and trolley mass arrangement demonstrating a horizontal kinetic interface connected over a corner pulley driven by an explicit 60N forcing function loop.
  • A. 3
  • B. 4
  • C. 2
  • D. 1.2

Solution

### Related Formula Kinetic friction force: f_k = mu_k N = mu_k m_1 g System acceleration: a = fracF_textpull - f_km_texttotal ### Core Logic Given values: Trolley mass m_1 = 20mathrm~kg, total system mass component in frame m_texttotal = 26mathrm~kg (from solution fraction frac60-826). Applied pulling force F = 60mathrm~N. mu_k = 0.04. Calculate the kinetic friction resisting the trolley: f_k = 0.04 times 20 times 10 = 8mathrm~N ### Step 1: Calculate Acceleration Using the dynamic equation for connected translation systems: a = frac60 - 826 = frac5226 = 2mathrm~ms^-2 ### Pattern Recognition Treat connected inline systems as a single collective mass block, balancing external driving forces against collective internal friction resistance. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Physics: Laws of Motion
Q36 jee_main_2024_29_january_evening Circular Motion and Tension
A stone of mass 900text g is tied to a string and moved in a vertical circle of radius 1text m making 10text rpm. The tension in the string, when the stone is at the lowest point is (if pi^2 = 9.8 and g = 9.8text m/s^2):
  • A. 97text N
  • B. 9.8text N
  • C. 8.82text N
  • D. 17.8text N

Solution

### Related Formula At the lowest point of a vertical circle, the equation of motion for a mass m is: T - mg = m r omega^2 Rearranging to solve for tension T: T = mg + m r omega^2 ### Core Logic Given data: * Mass, m = 900text g = 0.9text kg * Radius, r = 1text m * Frequency, N = 10text rpm = frac1060text rps = frac16text rps * Angular velocity, omega = 2pi N = 2pi left(frac16right) = fracpi3text rad/s ### Step 1: Calculate Force Values Now we substitute our parameters into the tension equation: T = (0.9)(9.8) + (0.9)(1)left(fracpi3right)^2 T = 8.82 + 0.9 times fracpi^29 Since pi^2 = 9.8: T = 8.82 + 0.1 times 9.8 T = 8.82 + 0.98 = 9.80text N
Free-body diagram of stone at lowest point in vertical circle for Q36
Free-body diagram of stone at lowest point in vertical circle for Q36
### Pattern Recognition Always convert Mass to textkg and rotational speed to textrad/s first. Using the prompt constraint pi^2 = 9.8 yields a perfect decimal addition match. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Physics: Laws of Motion
Q59 jee_main_2024_29_january_evening Non-uniform Circular Motion
A particle is moving in a circle of radius 50text cm in such a way that at any instant the normal and tangential components of its acceleration are equal. If its speed at t = 0 is 4text m/s, the time taken to complete the first revolution will be frac1alphaleft[ 1 - e^-2pi right]text s, where alpha = ________.
Numerical Answer. Answer: 8 to 8

Solution

### Related Formula For a particle in circular motion: * Normal (centripetal) acceleration: a_c = fracv^2r * Tangential acceleration: a_t = fracdvdt ### Core Logic Given a_c = a_t: fracv^2r = fracdvdt int_v_0^v fracdvv^2 = int_0^t fracdtr left[ -frac1v right]_v_0^v = fractr -frac1v + frac1v_0 = fractr implies frac1v = frac1v_0 - fractr v = fracv_01 - fracv_0 tr ### Step 1: Relate Velocity to Position and Integrate Substitute the parameters v_0 = 4text m/s and r = 50text cm = 0.5text m: v = frac41 - 8t = fracdsdt Integrating this to find the position s(t): int_0^s ds = int_0^t frac41 - 8t dt s = 4 left[ fracln(1 - 8t)-8 right]_0^t = -frac12 ln(1 - 8t) ### Step 2: Solve for Time of First Revolution To complete the first revolution, the distance covered is: s = 2pi r = 2pi (0.5) = pitext m Equating the distance: pi = -frac12 ln(1 - 8t) -2pi = ln(1 - 8t) 1 - 8t = e^-2pi 8t = 1 - e^-2pi implies t = frac18 left[ 1 - e^-2pi right]text s Comparing this to frac1alphaleft[ 1 - e^-2pi right]text s, we get: alpha = 8 ### Pattern Recognition The condition a_t = a_c implies v fracdvds = fracv^2r implies fracdvv = fracdsr. Integrating directly gives v = v_0 e^s/r. Substituting this back into v = ds/dt makes the final time integral much more intuitive. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Physics: Laws of Motion
Q36 jee_main_2024_27_jan_morning Banking of Tracks
A train is moving with a speed of 12text m/s on rails which are 1.5text m apart. To negotiate a curve of radius 400text m, the height by which the outer rail should be raised with respect to the inner rail is (Given, g = 10text m/s^2):
  • A. 6.0text cm
  • B. 5.4text cm
  • C. 4.8text cm
  • D. 4.2text cm

Solution

### Related Formula tantheta = fracv^2Rg For small angles, tantheta approx sintheta = frachd, where h is the raised height and d is the separation between the tracks. ### Core Logic Equating the two relationships: frachd = fracv^2Rg frach1.5 = frac12 times 12400 times 10 ### Step 1: Compute height value h = 1.5 times frac1444000 = 1.5 times 0.036 = 0.054text m Converting to centimeters: h = 0.054 times 100 = 5.4text cm ### Pattern Recognition Whenever theta is small, geometry permits approximating tantheta with frachtextwidth, vastly reducing computational transcendental overhead. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Physics: Laws of Motion

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