A watt is the rate of power of a system that transfers a joule of energy each second. A newton is the force of a system that transfers a joule of energy over the length of a meter. To convert from power to force, you therefore need to consider the time that a system runs and the distance that it covers. You also must use metric units because watts and newtons were designed around the metric system.
Multiply the system's power rating by the length of time it spends moving. For example, if a 500 watt system runs for 10 seconds: 500 --- 10 = 5,000. This is the amount of energy that it transfers, measured in joules.
Convert the distance the moving object travels from feet to meters by multiplying by 0.305. For example, if if covers 20 feet: 20 --- 0.305 = 6.1 m.
Divide the energy that the system transfers by the distance that it covers: 5,000 ÷ 6.1 = 819.67. This is the system's force, measured in newtons.
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