A student skates up a ramp that makes an angle 30 ° with the horizontal. He/she starts (as shown in the…

A student skates up a ramp that makes an angle 30° with the horizontal. He/she starts (as shown in the figure) at the bottom of the ramp with speed v0 and wants to turn around over a semicircular path xyz of radius R during which he/she reaches a maximum height h (at point y) from the ground as shown in the figure. Assume that the energy loss is negligible and the force required for this turn at the highest point is provided by his/her weight only. Then (g is the acceleration due to gravity)
  1. v02-2gh=12gR
  2. v02-2gh=32gR
  3. the centripetal force required at points x and z is zero
  4. the centripetal force required is maximum at points x and z

Solution

Speed at x and z is equal and also maximum in circular track.

From energy conversation,

12mv02=mgh+12mv2      .......(1)

at y, mgsin30°=mv2R

v2=Rg2

 From equation (1)

v02-2gh=Rg2

Asked in: JEE Advanced 2020 (Paper 2)

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