25. An electron has a kinetic energy of 2 MeV. What is its speed? (A) 1.4x10⁸ m/s (B) 2.4x10⁸ m/s (C) 2.94x10⁸ m/s (D) 3.8x10⁹ m/s

3. The moment of inertia of a solid sphere is 2MR²/5, hollow sphere is 2MR²/3, solid cylinder is MR²/2, and hollow cylinder is MR². All of the same mass M and the same outer radius R. If these four objects are released from rest at the top of an incline and start rolling without sliding. Which one will the last arrive at the bottom? (A) solid sphere (B) hollow sphere (C) solid cylinder (D) hollow cylinder

25. An electron has a kinetic energy of 2 MeV. What is its speed?

(A) 1.4x10⁸ m/s

(B) 2.4x10⁸ m/s

(C) 2.94x10⁸ m/s

(D) 3.8x10⁹ m/s

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