Acar engine changes chemical potential energy into the what energy so the car can move

The magnets are probably damaged or there not strong enough to attached to the refrigerator

The boat's velocity relative to the riverbank can be resolved into two components. the component going north is 2.7 m/s and the component going west is 1.2 m/s.we add these two vectors and then find the magnitude of the resultant to get the speed.the magnitude of the resultant vector from adding can be obtained by the pythagorean theorem.    to two significant figures, the boat's speed relative to the riverbank is 3.0 m/s.

The sunlight shines uv radiation on earth,a microwave oven radiates waves on food