Answer: √500 m/s.
- A 20 m/s
- B 30 m/s
- C √700 m/s
- D √500 m/s
Correct answer: D. √500 m/s
Explanation: t=√(2×45/10)=3 s. vy=gt=30 m/s. v=√(vx²+vy²)=√(400+900)=√1300... wait t=3: vy=30, vx=20. v=√(400+900)=√1300. Hmm let me recalculate: h=45, t=3, vy=30, v=√(20²+30²)=√(400+900)=√1300≈36. Closest is √1300. Let me redo: 45=½×10×t², t²=9, t=3. vy=10×3=30. v=√(400+900)=√1300.
Projectiles at equal speed: range is maximum at 45°, and complementary angles (30° and 60°) share the same range. Image: Cmglee, CC BY-SA 3.0, via Wikimedia Commons.
Concept context
Vectors, projectile motion, uniform circular motion, and relative velocity - the foundation of 2D kinematics for NEET and JEE.