Physics and acceleration

Question

An airplane lands and begins to slow down as it moves along the runway. If its mass is 2.80 ✕ 10^5 kg and the net braking force is 3.90 ✕ 10^5 N, what is the airplane’s acceleration?

Answer 1

Newton’s Second Law

Net Force = Mass * Acceleration

We are given:

mass = 2.80 x 10^5 kg

net force = 3.90 x 10^5 N

looking for: acceleration = ?

Plug in Force and Mass and solve for Acceleration

Force = mass * acceleration

3.90 x 10^5 = 2.80 x 10^5 x acceleration

Divide by 2.80 x 10^5 on both sides

***IMPORTANT!!!!****

YOU NEED TO USE PARENTHESIS WHEN YOU PLUG THIS INTO YOUR CALCULATOR

plug it in like this:

3.90x10^5 / (2.80x10^5) = 1.39 m/s^2

To get our final answer, we need to remember the context. The plane is SLOWING DOWN because of the braking force. A positive acceleration means speeding up and a negative acceleration means slowing down. To give an accurate answer, our acceleration should be NEGATIVE.

Acceleration a = -1.39m/s^2