Questions: 그림과 같이 36 m 높이에서 정지해 있던 질량이 10 kg 인 물체가 자유낙하하였다. 물체의 속력이 19.6 m / s 가 되는 순간의 높이 h 는? (단, 마찰과 공기 저항은 무시한다.) (1) 0 m (2) 16.4 m (3) 18.0 m (4) 20.4 m (5) 26.4 m

Solution Steps

• Initial height (H) = 36 m
• Mass (m) = 10 kg (not needed for this calculation)
• Final velocity (v) = 19.6 m/s
• Acceleration due to gravity (g) = 9.8 m/s²
• Required: Height (h) at which the velocity is 19.6 m/s

The kinematic equation for an object in free fall is: \[ v^2 = u^2 + 2gh \] where:

• \( v \) is the final velocity
• \( u \) is the initial velocity (0 m/s, since it starts from rest)
• \( g \) is the acceleration due to gravity
• \( h \) is the distance fallen

Substitute the known values: \[ (19.6)^2 = 0 + 2 \times 9.8 \times h \]

\[ 19.6^2 = 2 \times 9.8 \times h \] \[ 384.16 = 19.6h \] \[ h = \frac{384.16}{19.6} \] \[ h = 19.6 \]

The height at which the velocity is 19.6 m/s is: \[ H - h = 36 - 19.6 = 16.4 \, \text{m} \]

Final Answer