[问答题]
A British thermal unit n)e,hrenb 0e; (Btu) is a unigr0a x 44t 93d4arufdct of heat in the British system of units. One Btu is defined as t9f rrd u4 tcgdaa434x0he heat needed to raise 1 lb of water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J
