# Frames of Reference (1960)

601 words | 3 page(s)

The video, “Frames of Reference (1960),” provides a very detailed explanation as well as numerous examples as to how we view the world through different points of view. The video and the instruments that were used were very outdated but it was fascinating to see how such things could be explained through these simple measures. The video was entertaining and kept my attention throughout the educational references. This made learning about the frames of reference through inertial and non-inertial frames very interesting.

At the very beginning, the frame of reference was put into question as it was difficult to tell which speaker was standing upside down. Based on the direction a person is looking, all other things may look differently and, to each of the speakers, the other one clearly appeared to be upside down. The speakers used this to explain that the world is viewed through a point of few or within a frame of reference that is relative to the person who is viewing. It was then explained that all motion is relative to a frame of reference as it appears that the speaker is moving but the wall behind him is actually being moved. This is because one generally assumes that a wall is fixed to the floor which is fixed to the earth and the primary frame of reference is the earth.

The speakers continue to explain that the plane of the earth is viewed as horizontal or level and that we expect to see things relative to this plane. However, when the plane is moving, the viewer perceives the movement in relation to the earth unless they are in the frame of movement. This is shown by the slow motion camera being either fixed in motion or stationary when the ball drops. This is further explained as the cart rotates. Prior to rotation, it is clear that the puck is moving across the plane with constant velocity. When the frame of reference switches, it is explained that the puck moves forward or backwards at the velocity of puck plus or minus velocity of the cart. When the cart rotates, it appears that the puck is going in a circle but is actually going in a straight line. This gives the perception that there must be an additional force to the puck. The speakers explain that this is a fictitious force that we use to maintain the laws of inertia and other laws of physics.

The primary emphasis of the video was to show that things look differently through different frames of reference and that we often use fictitious forces and non-inertial frames to explain these differences. An inertial frame maintains the law of inertia as it is relative to the earth and holds at constant velocity. An accelerating force, such as the cart, is not an inertial frame and manipulates the way that a person views the motion based on the frame of reference. The speakers explain that this information is very important as understanding the motion of the earth, forces of gravity, and relationship to the stars are all highly dependent on understanding the frame of reference. The speakers add that the only true, or primarily true, stationary frame of reference is the stars as the earth is in constant motion. This was shown by the use of a pendulum and the straight line of the sand that was dropped from its motion. However, for all basic principles of the law of inertia, the speakers state that the use of the earth as the frame of reference supports the laws of physics and generally holds true.