Explain the Direct Billy method​

Thermal stresses are developed in a metal when its a) initial temperature is changed b) final temperature is changed c) density is changed d) thermal deformation is prevented e) expansion is prevented f) contraction is prevented

Afoot bridge is made as a simple deck, 4 m long, with a cross section 2 m (wide) and 20 cm thick, and made of wood. the deck is supported at the two ends. the maximum load allowable on the bridge is 10 tons, provided it is uniformly distributed on the deck. to sense this load, a strain gauge is placed at the center of the bridge and its resistance is monitored. if the sensor has a nominal resistance of 350 s2 and a gauge factor of 3.6, what is the reading of the strain gauge at maximum load? the modulus of elasticity for the wood used in the construction is 10 gpa.

There is a metal plate with thickness, thermal conductivity, density, and specific heat of 10 mm, 200 w/m.°c, 2500 kgrn3, and 900 j/kg. k, respectively. it has an initial uniform temperature of 22°c and is being heated in an oven for 2 minutes. air in the oven is maintained at 900 c with convection heat transfer coefficient of 190 w/m. k. determine the temperature of the plate when it is removed from the oven.