A50g mass of metal (c=0.20 cal/g°c) at 90°c is dropped into water at 30°c and the temperatures stabilized at 40°c.

100g
50g
2.0g
70g

50 g

Explanation:

Heat absorbed by water = heat lost by metal

mCΔT = mCΔT

m (1.00 cal/g/°C) (40°C − 30°C) = (50 g) (0.20 cal/g/°C) (90°C − 40°C)

m = 50 g

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explanation:

a longitudinal wave moves energy that is to the direction of the wave’s movement. - true