Question

1. an airplane with a mass of 50 mg lands on a runway with an initial speed of 80 m/s. a net external force of -3.2×10^5 n is required to bring the airplane to rest.

a. convert 50 mg to kilograms.
b. how long does it take for the airplane to come to rest?

Explanation:

Step1: Calculate the acceleration of the airplane

According to Newton's second law \(F = ma\), where \(F=- 3.2\times10^{5}\space N\) and \(m = 50\times10^{3}\space kg\).
We can solve for \(a\) as \(a=\frac{F}{m}\).
Substitute the values: \(a=\frac{-3.2\times 10^{5}}{50\times10^{3}}=- 6.4\space m/s^{2}\)

Step2: Use the kinematic equation \(v = v_{0}+at\) to find the time \(t\)

The final velocity \(v = 0\space m/s\), the initial velocity \(v_{0}=80\space m/s\), and \(a=-6.4\space m/s^{2}\)
From \(v = v_{0}+at\), we can solve for \(t\) as \(t=\frac{v - v_{0}}{a}\)
Substitute the values: \(t=\frac{0 - 80}{-6.4}=12.5\space s\)

Answer:

\(12.5\space s\)