Physics - Gravitation Question with Solution | TestHub

PhysicsGravitationEnergy & PotentialEasy2 minPYQ_2020
PhysicsEasysingle choice

An object is projected from the earth's surface with escape velocity at30°with horizontal. What is the angle made by the velocity with horizontal when the object reaches a height 2R from the earth's surface? R is the radius of the earth. Horizontal can be considered as a line parallel to the tangent at the earth's surface just below the object.

Options:

Answer:
C
Solution:

-GMmR  +  12mx2GMR=-GMm3R+12mv12

  v1=2GM3R

By conservation of angular momentum:

m×2GMRcos30°×R=m×v1cosθ×3R

cosθ=12  θ=60°

Subject:PhysicsTopic:GravitationSubtopic:Energy & Potential
2mℹ️ Source: PYQ_2020

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