Group - B Physics model question solution Part - 1 [NEB] 2077/78
GROUP - B 1.a) The sum of linear momentum of two colliding bodies is same before and after collision if no external forces acts on them. 1.c) In this case, aeroplane and earth acts as two colliding bodies and the momentum of aeroplane is transferred to earth. But the velocity of earth is too negligible to notice as it have large mass. That's how law of conservation of momentum works here. OR a). Hooke's law states that the restoring force produced in a body is directly proportional to the extension produced in it within elastic limit. b). Lets suppose the curve of deforming force w.r.t. strain be curve 'A' and the curve of reforming force be curve 'B'. As area of curve gives the work done by forces, the area of curve 'A' gives the work done by deforming force and the area of curve 'B' gives the work done by reforming force. According to figure, the work done by deforming force is greater than that of reforming force.
