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OthersQuestion and Answers: Page 128
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Question and Answers Forum |
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OthersQuestion and Answers: Page 128 |
| A ball falls vertically on to a floor, with momentum p, and then bounces repeatedly, the coefficient of restitution is e. The total momentum imparted by the ball to the floor is |
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| No work is done by a force on an object if (1) the object is stationary but the point of application of the force moves on the object (2) the object moves in such a way that the point of application of the force remains fixed (3) the force is always perpendicular to its velocity (4) the force is always perpendicular to its acceleration. |
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| A wooden block of mass 10 gm is dropped from the top of a tower 100 m high. Simultaneously, a bullet of mass 10 gm is fired from the foot of the tower vertically upwards with a velocity of 100 m/sec. If the bullet is embedded in it, how high will it rise above the tower before it starts falling? (Consider g = 10 m/sec^2 ) |
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| A rectangular wire frame ABCD is in vertical plane is moving with a constant acceleration a into the plane. Direction of gravity is shown in figure. A collar can move on wire AC of length l. Coefficient of friction between wire and collar is μ. Find (i) The minimum acceleration a so that collar does not slip on wire. (ii) The time taken by collar to reach C if acceleration is half the value calculated in part (i) |
| area of a(1−cos θ) |
| Which of the diagrams represents variation of total mechanical energy of a pendulum oscillating in air as function of time? |
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| Hybridisation of N in HNO_3 is |
| Which is correct statement? (1) The entropy of the universe increases and tends towards the maximum value (2) All natural processes are irreversible (3) For reversible isolated processes, change of entropy is zero (4) For irreversible expansion of isolated processes, entropy change < 0 |
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| Two blocks of masses 2 kg and 3 kg are kept on a smooth inclined plane. A constant force of magnitude 20 N is applied on 2 kg block parallel to the inclined. The contact force between the two blocks is |
| A women swimming upstream is not moving with respect to the ground. Is she doing any work, if she stops swimming and merely floats is work done on her? |
| Which of the following pair would correct inequality for standard molar entropy? (1) NO(g) < NO_2 (g) (2) C_2 H_2 (g) > C_2 H_6 (g) (3) CH_3 COOH (l) < HCOOH (l) (4) CO_2 (g) < CO(g) |
| Assertion: The first ionization energy of Be is greater than that of B. Reason: 2p-orbital is lower in energy than 2s-orbital. |
| A 50 g lead bullet, sp. heat 0.02 is initially at 30°C. It is fired vertically upwards with a speed of 840 m/s and on returning to the starting level strikes a cake of ice at 0°C. How much ice is melted? Assume that all energy is spent in melting only (L = 80 cal/g). |
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| A uniform chain of mass M and length L is hanging from the table. The chain is in limiting equilibrium when l length of chain over hangs. It is slightly disturbed from this position. Find the speed of the chain just after it completely comes off the table. |
| Assertion: Both N_2 and NO^+ are diamagnetic substances. Reason: NO^+ is isoelectronic with N_2 . |
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| The reaction CH_4 (g) + Cl_2 (g) → CH_3 Cl(g) + HCl(g) has ΔH = −25 kcal and bond dissociation energy of C − Cl, H − Cl, C − H and Cl − Cl is given as 84 kcal/mol, 103 kcal/mol, x kcal/mol and y kcal/mol respectively. Given x : y = 9 : 5, then bond energy of Cl − Cl bond in kcal/mol is |
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