A uniform horizontal beam 6m long has a mass of 0.5t and support at each end. the following mass are placed on the beam 2t at 1m from the left hand support and 4t and 2m from the right hand support sketch the arrangements and calculate the reaction at the support. take g as 9.81m/s. ​

Consider a 1000 w iron whose base plate is made of 0.5 cm thick aluminum alloy 2024-t6 (ρ = 2770 kg/m3 and cp = 875 j/kg°c). the base plate has a surface area of 0.03 m2. initially, the iron is in thermal equilibrium with the ambient air at 22°c. assuming 90% of the heat generated in the resistance wires is transferred to the plate, determine the minimum time needed for the plate temperature to reach 200°c.