projectile max height

Question

A ball is projected vertically upward with speed 18 m/s. Maximum height reached? (g = 9.8 m/s² ~ use 10 m/s² for simplicity)

RankGuru · Accepted Answer

1. **Point of Interest**: At maximum height ($H$), the velocity of the ball is momentarily zero ($v = 0$).
2. **Kinematic Equation**: $v^2 = u^2 - 2gH$.
3. **Constants**: Initial velocity ($u$) $= 18$ m/s, $g = 10 	ext{ m/s}^2$.
4. **Calculation**:
   - $0 = 18^2 - 2 	imes 10 	imes H$
   - $20H = 324$
   - $H = \frac{324}{20} = 16.2$ m.
5. **Verification**: Using $g = 9.8$ would give $H \approx 16.5$ m, but the simplified $16.2$ m is the intended answer for many competitive exams.

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projectile max height

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