The water in the river moves with the speed 0.523 km/h. Alice and Bob can swim with the speed 2.62 km/h with respect to the water. They want to get from point A on one bank of the river to point B directly across on the other bank. Alice swims along the straight line AB, while Bob swims with a velocity perpendicular to the river and lets the flow take him some distance downstream. After that, he walks to point B along the river. What is the speed of his walk if he reaches point B at the same time as Alice

Ablock of mass m = 2.5 kg is attached to a spring with spring constant k = 790 n/m. it is initially at rest on an inclined plane that is at an angle of 28 degrees with respect to the horizontal, and the coefficient of kinetic friction between the block and the plane is k = 0.14. in the initial position, where the spring is compressed by a distance of a = 0.18 m, the mass is at its lowest position and the spring is compressed the maximum amount. take the initial gravitational energy of the block as zero. b) if the spring pushes the block up the incline, what distance, l, in meters will the block travel before coming to rest? the spring remains attached to both the block and the fixed wall throughout its motion.

Amodel rocket with a mass of 0.212 kg is launched into the air with an initial speed of 84 m/s. how much kinetic energy will the rocket have at a height of 214 m? assume there is no wind resistance. 634 j 303 j

Directions: count the number of atoms. ar co2 na3po4 so3 nac2h3o2