What is the approximate period of this wave?

Keneila is attempting to ski down a 20 m high friction free hill for the first time. she has a speed 10 m/s at the top. what is her kinetic energy when she is a the bottom, 20 m ? (a)2500 j (b)9800 j (c)12300 j (d)3100j (e)15000j

What is the length x of the side of the triangle below? (hint: use the cosine function)

Does anyone have the answers to online physics course plato course physics, semester a v3.0