You finally decide to take some liquid nitrogen from the physics lab and freeze the 1.5 pounds of beans which were sitting in your vegetable basket at 20 c, rather than cook and eat them as your mother would have you do. beans are mostly water, like all living things. if the specific heat of water is approximately 1 cal/g/c and latent heat of fusion of water is approximately 80 cal/g, and the latent heat of vaporization of liquid nitrogen is 45 cal/g as measured by you, how much liquid nitrogen should you take from the lab (approximately)? you don't want to take a whole lot more than you really need.

A2 kg ball travellng to the right with a speed of 4 m/s collidees with a 5 kg ball traveling to the left with a speed of 3 m/s. take right to be the positive direction. what is the total momentum of the two balls before they collide? what is the total momentum of the two balls after they collide?

Apebble is thrown into a calm lake, ripples are formed from the center and move outward. the water particles in the lake travel in a circular pattern that moves up and down on the surface of a lake, and the energy travels a) diagonally. b) downward. c) horizontally. d) upward.

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.