Project ForgeA 60 mm-diameter water jet strikes a plate containing a hole of 40 mm diameter. Part of the jet (at 20 m/s) passes through the hole horizontally, and the remaining is deflected vertically (also leaving at 20 m/s). The density of water is 1000 kg/m³. The magnitude of horizontal force (in N) required to hold the plate is __________.
Explanation
Total incoming mass flow: ṁtotal = ρ·(π/4·0.06²)·20 ≈ 56.55 kg/s. Mass flow through the hole (retains horizontal velocity): ṁhole = ρ·(π/4·0.04²)·20 ≈ 25.13 kg/s. The deflected portion leaves with zero horizontal velocity component. Horizontal force on the plate = ṁtotal·V − ṁhole·V = (56.55−25.13)×20 ≈ 628.3 N.
Source: GATE ME 2017 Session 2 (ME-2) (2017)
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