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Newton's laws of motion are examined under conditions where the effects of gravity, friction and air resistance are eliminated or minimised.
Metadata describing this Open University video programme
Module code and title: S101, Science: a foundation course
Item code: S101; 03
First transmission date: 06-03-1979
Published: 1979
Rights Statement:
Restrictions on use:
Duration: 00:25:00
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Producer: John Stratford
Contributors: Stuart Freake; Steve Swithenby
Publisher: BBC Open University
Keyword(s): Air track; Conservation of momentum; Newton's laws; Richmond Ice Rink; Skylab; Weightlessness
Subject terms: Motion; Physics
Footage description: Film of astronauts exercising under weightless conditions in Skylab. Shots of a rubber ball bouncing from wall to wall in Skylab. Steve Swithenby introduces the programme. He points out that Newton's First Law is being obeyed by the bouncing ball in Skylab. 5withenby goes on to explain why motions of objects on earth appear so different from those in Skylab. Film of rugby balls being kicked and of Swithenby, in the studio, dropping a hammer and a feather simultaneously. Also film of the Apollo astronaut David Scott dropping a hammer and a feather simultaneously on the moon. Film shots of the David Scott experiment on the moon are shown again. Swithenby measures the time the hammer takes to reach the ground and then asks students to work out, from this data, the density of the moon. Swithenby pushes a coin across a table to demonstrate the effect of friction, another force which complicates the motion of objects here on earth. He points out that to demonstrate Newton's laws on earth clearly, it is desirable to eliminate or minimise such effects as friction and gravity. Shots of Stuart Freake at an ice rink. He points out that Newton's laws can be demonstrated on the ice directly because the frictional forces are very small. Shots of two skaters demonstrating the First Law. In order to demonstrate Newton's Second Law, two skaters are released, simultaneously, on the ice from catapults. Commentary by Freake explains the details of the experiment. Animated captions set out the mathematics involved. The experiment is performed again, this time under constant acceleration. The skaters go on to demonstrate Newton's Third Law. Commentary by Freake. Freeze frames and graphics help to illustrate the mathematics of the experiment. Brief film of a NASA rocket being launched. Steve Swithenby relates the story of an old editorial in the New York Times which lampooned the rocket pioneer Robert Goddard for his ideas that rockets could be propelled in outer space. He explains that if the editor had analysed the problem by using the conservation of momentum law, he might have avoided his error. As an alternative method of looking at Newton's laws, Swithenby sets up an experiment which examines conservation of momentum. The apparatus consists of an air track along which gliders of known mass travel. Animated graphics over shots of the experiment caption the mathematics of the experiment. Stuart Freake performs an experiment, on an air table which simulates the orbit of a satellite around the earth. The experiment demonstrates why objects in orbit appear to be weightless. An animation also helps to clarify some points. Over an animation showing the paths of the research craft Voyager 1 and 2 through the solar system, Steve Swithenby sums up the programme.
Master spool number: 6HT/72911
Production number: FOUS003H
Videofinder number: 1178
Available to public: no