# 6. Which object listed below is not accelerating?

a.) A person standing on the surface of the Earth.
b.) A satellite in geostationary orbit.
c.) A jet traveling at Mach 6.7 in a straight line.
d.) A child standing on a merry-go-round.
e.) A block oscillating on a spring when it reached its maximum amplitude.

c is a good guess, but a is not accelerating much either. Whether a jet is going in a straight line depends upon the coordinate system used. In a true inertial coordinate system, it is accelerating too

## To determine which object listed below is not accelerating, we need to understand the concept of acceleration and analyze each option.

Acceleration refers to how an object's velocity changes over time. It can be a change in speed, a change in direction, or both. If an object's velocity is constant, it is not accelerating.

Let's go through each option:

a.) A person standing on the surface of the Earth.
When a person is standing on the surface of the Earth, it may seem like they are not moving. However, the Earth is constantly rotating, which means the person is actually moving in a circular path around the Earth's axis. This circular motion causes a change in direction, and therefore, the person standing on the Earth's surface is actually accelerating.

b.) A satellite in geostationary orbit.
A satellite in geostationary orbit appears to be stationary when observed from the Earth's surface. However, it is actually moving in a circular orbit around the Earth. This circular motion creates a continuous change in direction, resulting in acceleration.

c.) A jet traveling at Mach 6.7 in a straight line.
When a jet is traveling in a straight line at a constant speed, it does not change direction. If the speed remains constant, it is also not changing in magnitude. Hence, it is not accelerating. Therefore, option c is the correct answer, and the jet traveling at Mach 6.7 in a straight line is not accelerating.

d.) A child standing on a merry-go-round.
When a child is standing on a merry-go-round, the merry-go-round itself is rotating. The child's position on the merry-go-round is constantly changing, resulting in a change in direction. Thus, the child is accelerating.

e.) A block oscillating on a spring when it reaches its maximum amplitude.
An oscillating object is constantly changing its position due to the alternating forces of the spring. When the block reaches its maximum amplitude, it is momentarily at rest before reversing its direction. At this point, the block's velocity is zero, but it still experiences a change in direction, indicating acceleration.

In conclusion, among the given options, the object not accelerating is option c - the jet traveling at Mach 6.7 in a straight line.