IGNOU BPHCT 131 Mechanics Question Paper 2025 | BPHCT 131 Question Paper 2025 in English with Solutions
Here you can download BPHCT 131 Important Questions June 2025 with answers in english IGNOU BPHCT 131 Question Paper 2025 Pdf in English BPHCT 131 Mechanics Question Paper June 2025 in English BPHCT 131 Paper 2025 BPHCT 131 Question Paper 2025
BACHELOR OF SCIENCE (B. Sc.) (BSCG)
Term-End Examination June, 2025
BPHCT-131 : MECHANICS
Time : 2 Hours Maximum Marks : 50
Note : (i) Attempt all questions.
(ii) The marks for each question are indicated against it.
(iii) Symbols have their usual meanings.
(iv) You may use a calculator
1. Answer any five parts :
(a) Show that for any two vectors p and q :
(c) In the following cases identify the inertial and non-inertial frames, giving reasons :
(i) A ball being swung in a circle
(ii) A car moving in a straight line at constant speed
(d) Calculate the impulse for a ball of mass 20 g which strikes a wall straight with a speed of 10 ms–1 and rebounds at the same speed.
(e) What is the rotational K. E. of a particle of mass 2 kg moving in a circle of radius 1 m with an angular speed of 1 rad s–1
(f) State Kepler’s law of harmonics for planetary motion.
(g) Write the differential equation for the motion of a one-dimensional spring-mass system. What is its frequency of oscillation in terms of the force constant of the spring and the mass ?
(h) Are water waves transverse or longitudinal ? Explain your answer
2. Answer any two parts :
(b) Solve the following boundary value problem : 16y” + y = 0, y(0) = 2, y(2pi) = – 3
(c) A curve is represented by the following parametric equations :
x = 4, y = t2 + 6, z = 3 – 2t
Determine the unit tangent vector to the curve at t = 1.
BPHCT 131 : Mechanics Question Paper June 2025 in English
3. Answer any two parts :
(a) A ship of mass 4 × 10^8 kg is moving at a constant velocity. Its engine generates a forward thrust of 8 × 105 N . Determine
(i) the upward bouyant force on the ship due to water and (ii) the resistive force exerted by water on the ship. Take g = 10 m/s2
(b) State the law of conservation of energy. A block of mass 1·5 kg is pushed against a spring kept on a table and compresses it by 20 cm. Then the block is released and it slides along the table. If the coefficient of kinetic friction between the block and the table is 0·2 and the spring constant is 150 Nm–1 , how far will the block move before it comes to rest ? Take g = 10 ms–2
(c) (i) If the force of friction is 20 N, what power is needed to maintain a steady speed of an object at 2.0 ms
(ii) A woman of mass 80 kg and her car are suddenly accelerated from rest to a speed of 6.0 ms on level ground ? as a result of rearend collision. Obtain the impulse on the woman and the average force exerted on her if the duration of the collision is 0.8 s
BPHCT 131 Important Questions with Answers
4. Answer any two parts :
(a) (i) A girl is sitting on a giant wheel at a distance of 5.0 m from its centre. What is her speed when the wheel is turning at the rate of 1 revolution every 5 s ?
(ii) What are the constants of motion for motion under central conservative forces ? Derive the Law of Equal Areas for central force motion
(b) (i) What is a central force ? What are the two constants of motion under central conservative forces ?
(ii) Determine the centre of mass and relative coordinates of a system consisting of two particles of masses of 1.5 kg and 2.5 kg placed 3.0 m apart.
(c) Derive the expression for the total kinetic energy of a two-particle system in terms of the velocity of its c.m. and the velocities of the particles with respect to the c.m
5. Answer any two parts :
(a) (i) The amplitude of oscillation of a simple harmonic oscillator is 40 cm. Show that its instantaneous kinetic energy is less than its average kinetic energy when the displacement is 30 cm
(ii) An object undergoes SHM with frequency f = 0.45 Hz. The initial displacement is 0.025 m and the initial velocity is 1.5 ms–1. Calculate the amplitude of the oscillation
Write the solution of this differential equation for the following set of initial conditions :
(b) A travelling wave is given by : y xt ( , 0.18 ) = sin (10.2 3.2 1.8) t x − + m where x is measured in metres and t is measured in seconds. Determine the distance by which the origin on the x-axis should be shifted so that the expression for the wave becomes : y xt ( , 0.18 sin 10.2 3.2 ) = ( t x − ) m
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