A firefighter of mass stands at rest on frictionless horizontal ice while holding a…
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A firefighter of mass 60kg stands at rest on frictionless horizontal ice while holding a portable fire extinguisher. When the valve is opened, the extinguisher ejects 2.0kgs−1 of carbon-dioxide gas at a speed of 20ms−1 relative to the nozzle for a continuous interval of 5.0s. The mass of gas contained in the cylinder before discharge is 10kg and the mass of the empty cylinder can be taken as 6.0kg. Assume no external horizontal forces act on the system.
(i) Calculate the speed of the firefighter–cylinder system immediately after the gas flow stops.
(ii) Determine the kinetic energy acquired by the firefighter–cylinder system at that instant.