A van is standing on a frictionless portion of a horizontal road. To start the engine, the vehicle must be set in motion in theforward direction. How can the persons sitting inside the van do it without coming out and pushing from behind?

A block of mass m sits at rest on a frictionless table in a rail car that is moving with speed v_(c) along a straight horizontal track (fig.) A person riding in the car pushes on the block with a net horizontal force F for a time t in the direction of the car's motion. According to a person standing on the ground outside the train ?

A block of mass m sits at rest on a frictionless table in a rail car that is moving with speed v_(c) along a straight horizontal track (fig.) A person riding in the car pushes on the block with a net horizontal force F for a time t in the direction of the car's motion. How much did K.E of the block change according to the person in the car ?

A block of mass m sits at rest on a frictionless table in a rail car that is moving with speed v_(c) along a straight horizontal track (fig.) A person riding in the car pushes on the block with a net horizontal force F for a time t in the direction of the car's motion. In terms of F,m & t , how far did the the force displace the object according to the person in car ?

A plumb bob is hung from the ceiling of a train compartment. If the train moves with an acceleration a along a straight horizontal track, the stirng suporting the bob makes an angle tan^1 (a/g) with the normkal to the ceiling. Suppose the train moves on an inclined straight track with uniform moves on aninclined straight track with uniform velocity. If the angle of incline is tan^-1(a/g) , the string again makes the same angle with the normal to the ceiling. Can a person sitting inside the compartment tell by lookign at the plumb line whether the train is accelerated on a horizontal straight track or it is going on an incline? If yes, how? If no, suggest a method to do so.

There are five cities A, B, C, D, E on a certain island. Each city is connected to every other city by road. In how many ways can a person starting from city A come back to A after visiting some cities without visiting a city more than once and without taking same road more than once? (The order in which he visits the cities also matters: e.g. the routes A->B->C->A and A->C->B->A are different