A ²³⁸U nucleus decays by emitting an alpha particle of speed v ms^–1. The recoil speed of the residual nucleus is (in ms^–1) 

(1) –4v/234

(2) v/4

(3) –4v/238

(4) 4v/238

A smooth sphere of mass M moving with velocity u directly collides elastically with another sphere of mass m at rest. After collision their final velocities are V and v respectively. The value of v is 

(1) $\frac{2uM}{m}$

(2) $\frac{2um}{M}$

(3) $\frac{2u}{1+\frac{m}{M}}$

(4) $\frac{2u}{1+\frac{M}{m}}$

A particle of mass m moving with horizontal speed 6 m/sec as shown in figure. If m << M then for one dimensional elastic collision, the speed of lighter particle after collision will be 

(1) 2m/sec in original direction

(2) 2 m/sec opposite to the original direction

(3) 4 m/sec opposite to the original direction

(4) 4 m/sec in original direction

A shell of mass m moving with velocity v suddenly breaks into 2 pieces. The part having mass m/4 remains stationary. The velocity of the other shell will be 

(1) v

(2) 2v

(3) $\frac{3}{4}v$

(4) $\frac{4}{3}v$

A body falls on a surface of coefficient of restitution 0.6 from a height of 1 m. Then the body rebounds to a height of 

(1) 0.6 m

(2) 0.4 m

(3) 1 m

(4) 0.36 m

A particle falls from a height h upon a fixed horizontal plane and rebounds. If e is the coefficient of restitution, the total distance travelled before rebounding has stopped is 

(1) $h\left(\frac{{\displaystyle 1+e^2}}{{\displaystyle 1-e^2}}\right)$

(2) $h\left(\frac{{\displaystyle 1-e^2}}{{\displaystyle 1+e^2}}\right)$

(3) $\frac{h}{2}\left(\frac{{\displaystyle 1-e^2}}{{\displaystyle 1+e^2}}\right)$

(4) $\frac{h}{2}\left(\frac{{\displaystyle 1+e^2}}{{\displaystyle 1-e^2}}\right)$

A body of mass 5 kg moving with a velocity 10m/s collides with another body of the mass 20 kg at, rest and comes to rest. The velocity of the second body due to collision is 

(1) 2.5 m/s

(2) 5 m/s

(3) 7.5 m/s

(4) 10 m/s

A ball of mass m moving with velocity V, makes a head on elastic collision with a ball of the same mass moving with velocity 2V towards it. Taking direction of V as positive, velocities of the two balls after collision are-

(1) –V and 2V

(2) 2 V and –V

(3) V and –2V

(4) –2V and V