Phương trình chuyển động của một chất điểm dọc theo trục Ox có dạng: x = 20 + 40t (km, h). a. Xác định tọa độ của vật lúc bắt đầu xét chuyển động, lúc t = 1h.

b. Vẽ đồ thị x(t)

Distinguish between a transverse wave and a longitudinal wave.

Steelhead trout migrate up stream to spawn. occasionally they need to leap up small waterfalls to continue their journey. fortunately, steelhead are remarkable jumpers, capable of leaving the water at a speed of 8.0 m/s. a. what is the maximum height a steelhead trout can jump? b. leaving the water at 8.0 m/s, the trout lands on top of the water fall 1.8 m high. how long was it in the air?

Which best describes the first law of thermodynamics as compared to the second law of thermodynamics? a. the first law describes how thermal energy is conserved but not the direction it moves. b. the first law describes the direction thermal energy moves but not how it is conserved. c. the first law describes how thermal energy can be created but not how it can be destroyed. d. the first law describes how thermal energy can be destroyed but not how it can be created.