Airplane with nose up: The plane's speed through the air is the square root of (80 m/s squared) plus (120 m/s squared. The whole picture is a right triangle, and the plane's speed is the hypotenuse. The angle is the angle whose tangent is (80/120). You can get it from a calculator, a book, a slide rule, or online from the site that rhymes with floogle.
The man pulling the load is also a right triangle. The horizontal component is (hypotenuse) times (cosine of the angle). The vertical component is (hypotenuse) times (sine of the same angle). Fill in what you know, look up the sin and cos of 25 degrees and write those in too, and then you can solve for what you have to find.
When the water freezes the kinetic energy decreases because it is staying in place instead of moving around, which also causes thermal energy to decrease.
