Questions: 3. If your friend drops a chocolate bar to you from a height of 5.0 m above your hands, (a) How long would it take you to catch it? Use Eq. 2.
height = 5.0 m
initial (0, ? )
h = V1 t + 1 / 2
g = 9.8 m / s^2
t = sqrt(2 h / 9)
t = sqrt(2 * 5.0 m) / 9.8 m / s^2
≈ 1.0102 s
t = sqrt(1.8 / 9 .8) t = sqrt(1.0204)
(b) With what speed will the chocolate bar strike your hands? Use Eq. 3.
g = 9.8 m / s^2 ≈ 1.0102 s
h = 5.0 m
v = g t → 9.9 m / s^2 × 1.01025
≈ 9.8996 mb
(c) In the previous part, what would the speed equal if you had incorrectly used Eq. 1 instead?
(d) Why is using Eq. 1 incorrect in this problem?
Transcript text: 3. If your friend drops a chocolate bar to you from a height of 5.0 m above your hands, (a) How long would it take you to catch it? Use Eq. 2.
\[
\begin{array}{l}
\text { height }=5.0 \mathrm{~m} \\
\text { initial }(0, \text { ? }) \\
h=V_{1} t+1 / 2 \\
g=9.8 \mathrm{~m} / \mathrm{s}^{2} \\
t=\sqrt{\frac{2 h}{9}} \\
t=\frac{\sqrt{2 \times 5.0 \mathrm{~m}}}{9.8 \mathrm{~m} / \mathrm{s}^{2}} \\
\approx 1.0102 \mathrm{~s} \\
t=\sqrt{\frac{1.8}{9} .8} \quad t=\sqrt{1.0204}
\end{array}
\]
(b) With what speed will the chocolate bar strike your hands? Use Eq. 3.
\[
\begin{array}{l}
g=9.8 \mathrm{~m} / \mathrm{s}^{2} \approx 1.0102 \mathrm{~s} \\
h=5.0 \mathrm{~m} \\
v=g t \rightarrow 9.9 \mathrm{~m} / \mathrm{s}^{2} \times 1.01025 \\
\approx 9.8996 \mathrm{mb}
\end{array}
\]
(c) In the previous part, what would the speed equal if you had incorrectly used Eq. 1 instead?
(d) Why is using Eq. 1 incorrect in this problem?
Solution
Solution Steps
Step 1: Calculate the Time to Catch the Chocolate Bar
To find the time it takes for the chocolate bar to fall 5.0 m, we use the equation for free fall:
\[
t = \sqrt{\frac{2h}{g}}
\]
Substitute \( h = 5.0 \, \text{m} \) and \( g = 9.8 \, \text{m/s}^2 \):
Equation 1 is not provided, but typically, if an incorrect equation is used, it might not account for the correct physics of free fall. Without the specific equation, we cannot calculate the incorrect speed.
Final Answer
(a) The time to catch the chocolate bar is \(\boxed{1.0102 \, \text{s}}\).
(b) The speed at which the chocolate bar strikes your hands is \(\boxed{9.8996 \, \text{m/s}}\).