JEE Mains · Physics · STD 11 - 3.2 motion in plane
A projectile is thrown upward at an angle \( 60^{\circ} \) with the horizontal. The speed of the projectile is 20 m/s when its direction of motion is \( 45^{\circ} \) with the horizontal. The initial speed of the projectile is __________ in m/s.
- A \( 40\sqrt{2} \)
- B 40
- C \( 20\sqrt{3} \)
- D \( 20\sqrt{2} \)
Answer & Solution
Correct Answer
(D) \( 20\sqrt{2} \)
Step-by-step Solution
Detailed explanation
\( u~cos~60^{\circ}=\frac{20}{\sqrt{2}} \) \( \frac{u}{2}=\frac{20}{\sqrt{2}} \) \( u=\frac{40}{\sqrt{2}} \) \(u =20 \sqrt{2}\) m/s
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