An object is dropped from a height of \(15 \ \text{m}\). a) How long does it take for the object to reach the ground? b) What is its final velocity just before hitting the ground? Use \( g = 9.8 \ \text{m/s}^2 \) for the acceleration due to gravity.

Question

**Problem: Falling Object**  An object is dropped from a height of \(15 \ \text{m}\). a) How long does it take for the object to reach the ground? b) What is its final velocity just before hitting the ground? Use \( g = 9.8 \ \text{m/s}^2 \) for the acceleration due to gravity. 

Answer 1

\[ \begin{array}{l} S=15 m \\ u=0 \\ a=9.8 m / s ^{2} \\ t=? \\ v=? \end{array} \] using \( v^{2}=u^{2}+2 \) as \[ \begin{array}{l} v^{2}=(0)^{2}+2(9.8) \times 15 \\ v^{2}=294 \Rightarrow v=17.15 \end{array} \] using \( v=u+a t \) \[ \begin{aligned} 17.15 & =0+(9.8) \times t \\ t & =\frac{17.15}{9.8} \\ t & =1.75 s \end{aligned} \]