1. A person standing motionless between a straight highway and an airport runway. A truck drives by the person at constant speed, while an airplane accelerates down the runway for take off. Of the person, truck, and airplane, which are an inertial frame of reference?
A. truck and airplane only
B. person and truck only
C. person only
D. person, truck, and airplane
Help
All inertial frames are in a state of constant, rectilinear motion with respect to one another; an accelerometer moving with any of them would detect zero acceleration.
The airplane cannot be in the inertia frame of reference, it is accelerating.
To determine which of the person, truck, and airplane are an inertial frame of reference, we need to understand the concept of an inertial frame of reference.
An inertial frame of reference is a reference frame in which laws of motion hold true and objects in this frame will experience no acceleration if no external forces act upon them. In other words, if an object appears to be at rest or moving with a constant velocity in one frame of reference, it will also appear to be at rest or moving with a constant velocity in any other inertial frame of reference.
Now, let's analyze the situation given:
1. The truck drives by the person at a constant speed: Since the truck is moving with a constant speed, it is experiencing no acceleration. Therefore, the truck is an inertial frame of reference.
2. The airplane is accelerating down the runway for takeoff: Acceleration indicates a change in velocity, which means the airplane is not moving with a constant velocity. Therefore, the airplane is not an inertial frame of reference.
3. The person is standing motionless: Since the person is not moving at all, they are also an inertial frame of reference.
Based on the analysis, the correct answer is:
D. person, truck, and airplane.
Both the person and the truck are experiencing no acceleration, whereas the airplane is accelerating.