A body is moving in a circle at a uniform speed v. What is the magnitude of the change in velocity when the radius vector describes an angle ?


Correct option is


AB and CD represent the two velocity vectors. The change in velocity is . To find , we reverse the direction of vector AB. Now,AB represents –v1. Shift vector CD parallel to itself till its tail is at the head of vector AB. From parallelogram law, vector BE represent . The magnitude of  is given by 








A train rounds an unbanked circular bend of radius 50 m at a speed of 54 km h–1. If g = 10 ms–2, the angle of banking required to prevent wearing out of rails is given by