NEET and AIPMT NEET Physics Systems of Particles and Rotational Motion MCQ Questions Solved


A block of mass m moving at a velocity v collides with another block of mass 2m at rest. The lighter block comes to rest after collision. Find the coefficient of restitution.

(a) 12                                               (b) 1

(c) 13                                               (d) 14

From conservation of linear momentum we can see that velocity of 2m will become v2 after collision (as mass is doubled)

              

      Now,                             e=Relative velocity of separationRelative velocity of approach                                         =V/2V=12

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PMT - 2011

A small mass attached to a string rotates on a frictionless table top as shown. If the tension on the string is increased by pulling the string causing the radius of the circular motion to decrease by a factor of 2, the kinetic energy of the mass will

                              

(a) Increase by a factor of 4                                       (b) Decrease by a factor of 2

(c) Remain constant                                                   (d) Increase by a factor of 2 

(a)        K.E.=L22I              From angular momentum conservation about centre              L  constant              I=mr2              K.E.'=L22mr'2        r'=r2              K.E.'=4 K.E.              K.E. is increased by a factor of 4.

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Three point masses ,m, each are placed at the vertices of an equilateral triangle of side a. Moment of inertia of the system about an axis COD passing through a mass m at and lying in the plane of COA & perpendicu- lar to OA is A) 2 ma (C) ^ ma? 7 na

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PMT - 2006
A solid sphere rools down two different in- clined planes of same height, but of differ- ent inclinations. In both cases (A) speed and time of descent will be same (B) speed will be same, but time of descent will be different scent will be same diffferent (C) speed will be different, but time of de- (D) speed and time of descent both are (UP CPMT 2006)

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PMT - 2004
A wheel having moment of inertia 2 kg- m2 about its vertical axis, rotates at the rate of 60 rpm about this axis. The torque which cah stop the wheel's rotation in one minute would be [CBSE PMT 2004; Kerala PMT 2004] 2π (a) 쓸Nm 15 (b) Nm 12 (d) LNm 18 15

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The principle of conservation of angular momentum, states that angular momentum (a) Always remains conserved (b) Is the product of moment of inertia and velocity (c) Remains conserved until the torque acting on it remains [BHU 2000] constant (d) None of these

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A particle is moving in a circular orbit with constant speed. Select wrong alternate. (a) Its linear momentum is conserved (b) Its angular momentum is conserved (c) It is moving with variable velocity (d) It is moving with variable acceleration

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ABC is a right angled triangular plate of uniform thickness. The sides are such that AB> BC as shown in figure. I, I2 and I3 are moments of inertia about AB, BCand AC respectively Then, which of the following relation is correct? 3 2 (a) 2 13 (c) 13 < 12 < 11 (b) I2 > I1> I3 (d) I3 > 11> I2

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One solid sphere A and another hollow sphere B are of same mass and same outer radii. Their moment of inertia about their di- ameters are respectively lA and lg such that (A) IA9 (B) A le (C) Aa

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PMT - 1997
A couple produces NTSE 1995; CBSE PMT 1997; DCE 2004] (a) Purely linear motion (b) Purely rotational motion (c) Linear and rotational motion (d) No motion

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