A jet travels from east to west at 500 km h⁻¹ and ejects gases at 1500 km h⁻¹ relative to the plane, backward relative to the jet. What is the gas velocity relative to ground?
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Question

A jet travels from east to west at 500 km h⁻¹ and ejects gases at 1500 km h⁻¹ relative to the plane, backward relative to the jet. What is the gas velocity relative to ground?

G1 Physics · Accepted Answer

Take east as positive. Jet velocity=-500 km h⁻¹. Exhaust relative to jet is +1500 km h⁻¹ eastward. Hence gas ground velocity=-500+1500=+1000 km h⁻¹, west to east. Option A.