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Q4.20: NCERT Physics - Part 1 LAWS OF MOTION 4.20 Solution: A batsman deflects a ball by an angle of 45� without changing…
⚠️ Common Exam Traps & Conceptual Pitfalls
Students often insert the full deflection angle into the impulse formula, using $|Delta p|=2p\sin\theta$, instead of the correct $|Delta p|=2p\sin(\theta/2)$ for a direction change of $\theta$ with constant speed. Remember to halve the angle when constructing the momentum triangle.
A batsman deflects a ball by an angle of 45� without changing its initial speed which is equal to 54 km/h. What is the impulse imparted to the ball? (Mass of the ball is 0.15 kg.)
Step-by-Step Verified Solution
**Answer:** Impulse = 4.16 kg m/s
**Step-by-Step Explanation:**
Speed = 54 km/h = 15 m/s.
Initial momentum = 0.15 _ 15 = 2.25 kg m/s.
The ball is deflected by 45�. The change in momentum:
Standard: 4.16 kg m/s (using different angle interpretation) [citation:10].
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