A boat moves relative to water with a velocity with a velocity v is n times less than the river flow u. At what angle to the stream direction must the boat move to minimize drifting ?

A rocket is moving up with a velocity v, if the velocity of this rocket is suddenly tripled, what will be the ratio of two kinetic energies?

What is the momentum of an object of mass m moving with velocity v ?

Figure shows a conducting rod PQ in contact with metal rails RP and SQ, which are 0.25 m apart in a uniform magnetic field of flux density 0.4T acting perpendicular to the plane of the paper. Ends R and S are connected through a 5 Omega resistance. What is the emf when the rod moves to the right with a velocity of 5ms^(-1) ? What is the magnitude and direction of the current through the 5 Omega resistance? If the rod PQ moves to the left with the same speed, what will be the new current and its direction?

A particle moves in a circle of radius r with constant angular velocity omega . What is the change in velocity when the particle describe an angle of 90^@ ?

A body is projected with a velocity u in a direction making angle theta with the horizontal. Show that path of the projectile is a parabola. Find the maximum heighth reached, the time of flight and horizontal range.

A particle of charge ‘q’moves with a velocity v at an angle ‘0’ to a magnetic field ‘B’. What is the force experienced by the particle ?

In a wire of cross-section radius r, free electrons travel with drift velocity v when a current I flows through the wire. What is the current in another wire of half the radius and of the same material when the drift velocity is 2v?

What is the apparent change in frequency when source and observer move with same velocity in the same direction?

An express train is moving with a velocity v_1 . Its driver finds another train is movig on the same track in the same direction with velocity v_2 . To escape collision, driver applies a retardation a on the train. The minimum time of escaping collision be