Work, Power and EnergyHard
Question
A stone tied to a string of length L is whirled in a vertical circle with the other end of the string at the centre. At a certain instant of time, the stone is at its lowest position, and has a speed u, The magnitude of the change in its velocity as it reaches a position, where the string is horizontal, is
Options
A.

B.

C.

D.

Solution
From energy conservation v2 = u2 - 2gL ....(i)
Now, since the two velocity vector shown in figure are mutually perpendicular, hence the magnitude of change of velocity will be given by
Substituting value of v2 from Eq. (i)

Create a free account to view solution
View Solution FreeMore Work, Power and Energy Questions
A Carnot engine, having an efficiency of as heat engine, is used as a refrigerator. If the work done on the system is 10...A mass of 12 kg at rest explodes into two pieces of masses 4 kg and 8 kg which move in opposite directions. If the veloc...A force = (3x2+2x−7) N acts on a 2 kg body as a result of which the body gets displaced from x = 0 to x = 5m. The ...A particle of mass 100 g is thrown vertically upwards with a speed of 5 m/s. the work done by the force of gravity durin...A particle moves in a potential region given by U = 8x2 - 4x + 400 J. Its state of equilibrium will be -...