Watt

The watt (symbol: W) is a derived unit of power in the International System of Units (SI), named after the Scottish engineer James Watt (1736–1819). The unit is defined as joule per second and can be used to express the rate of energy conversion or transfer with respect to time. It has dimensions of L²MT⁻³.

Examples

When an object's velocity is held constant at one meter per second against constant opposing force of one newton the rate at which work is done is 1 watt.

In terms of electromagnetism, one watt is the rate at which work is done when one ampere (A) of current flows through an electrical potential difference of one volt (V).

Two additional unit conversions for watt can be found using the above equation and Ohm's Law.

Where ohm () is the SI derived unit of electrical resistance.

DeLorean time machine

The DeLorean time machine is a fictional automobile-based time travel device featured in the Back to the Future franchise. In the feature film series, Dr. Emmett Brown builds a time machine based on a DeLorean DMC-12 car, to gain insights into history and the future. Instead, he ends up using it to travel over 130 years of Hill Valley history (from 1885 to 2015) with Marty McFly to change the past for the better and to undo the negative effects of time travel. One of the cars used in filming is on display at Universal Studios Hollywood.

Operation

The control of the time machine is the same in all three films. The operator is seated inside the DeLorean (except the first time, when a remote control is used), and turns on the time circuits, activating a unit containing multiple fourteen- and seven-segment displays that show the destination (red), present (green), and last-departed (yellow) dates and times. After entering a target date, the operator accelerates the car to 88 miles per hour (141.6 km/h), which activates the flux capacitor. As it accelerates, several coils around the body glow blue/white. Surrounded by electrical current similar to a Tesla coil, the whole car vanishes in a flash of white/blue light seconds later, leaving a pair of fiery tire tracks. A digital speedometer is attached to the dashboard so that the operator can accurately gauge the car's speed. Various proposals have been brought forth in the past by fans of the movie franchise for why the car has to be moving at 88 mph to achieve temporal displacement, but actually the production crew chose the velocity simply because they liked how it looked on the speedometer.