Physics Test 117

A particle collides elastically with two moving walls one by one as shown on a horizontal plane. Find the final speed of the particle after two collisions :

Both bodies released in free space with initial separation 12R. The distance covered by the smaller body just before the collision will be :-

A piece of paper (shown in figure 1) is in the form of a square. Two corners of this square are folded to make it appear like figure-2. Both corners are put together at centre of square 'O'. If 'O' is taken to be (0, 0), the centre of mass of new system will be :

A conducting rod with resistance r per unit length is moving inside a vertical magnetic field  at constant speed v on two horizontal parallel ideal conductor rails. The ends of the rails are connected to a resistor R. The separation between the rails is d. The rod maintains a tilted angle θ to the rails. Find the external force required to keep the rod moving.

A small circular loop is suspended from an insulating thread. Another coaxial circular loop carrying a current I and having radius much larger than the first loop starts moving towards the smaller loop. The smaller loop will

A light spring is permanently connected between two trolleys of masses M and m which can move over a smooth horizontal table, along a straight line parallel to the length of the spring as shown in figure. The trolleys are brought nearer to compress the spring and then released. For the subsequent motion of the given system choose the CORRECT statement(s). (Consider both trolleys and spring as a single system)

A particle of unit mass collides elastically with ground at an angle 45°. Then :-

A circular conducting loop of radius r₀ and having resistance per unit length λ as shown in the figure is placed in a magnetic field B which is constant in space and time. The ends of the loop are crossed and pulled in opposite directions with a velocity v such that the loop always remains circular and the radius of the loop goes on decreasing, then

Diagram shows a cylindrical magnetic field increasing at B₀ per second. ABCD is a rectangular loop. AB being diameter (2R) of field. EMF (magnitude) across :-

A particle strikes a horizontal smooth floor with a velocity u making an angle θ with the floor and  rebounds with velocity v making an angle ϕ with the floor. If the coefficient of restitution between the particle and the floor is e, then : 

The impulse delivered by the floor to the body is