JEE Advanced2013PhysicsWork, Power and EnergyActual
Paragraph: A small block of mass 1 ~kg is released from rest at the top of a rough track. The track is a circular arc of radius 40 ~m . The block slides along the track without toppling and a frictional force acts on it in the direction opposite to the instantaneous velocity. The work done in overcoming the friction up to the point Q , as shown in the figure below, is 150 ~J . (Take the acceleration due to gravity, g
Options
- A5 ms - 1
- B10 ms - 1
- C10 3 ms -1
- D20 ms - 1
Correct answer
B. 10 ms - 1
Step-by-step solution
Apply conservation of energy, ∆ P E - W f = ∆ K E M g R sin 30 ° - 150 = 1 2 M v 2 M g R 2 - 150 = 1 2 M v 2 ⇒ 1 × 10 × 20 - 150 = 1 2 × 1 × v 2 ⇒ v = 10   m   s - 1