Very urgent more urgent then anything. urgent urgent how is a pure substance different from a mixture?a. mixtures can be separated by physical means. b. pure substances are made up of mixtures. c. a pure substance is heterogeneous. d. a mixture is made of one substance.

What is the final velocity of the initial velocity of 25 and -50?

Awater-filled u-tube manometer is used to measure the pressure inside a tank that contains air. the water level in the u-tube on the side that connects to the tank is 5 ft above the base of the tank. the water level in the other side of the u-tube (which is open to the atmosphere) is 2 ft above the base. determine the pressure within the tank.

Henry, whose mass is 95 kg, stands on a bathroom scale in an elevator. the scale reads 830 n for the first 2.4 s after the elevator starts moving, then 930 n for the next 2.4 s. part a what is the elevator's speed 4.8 s after starting? express your answer with the appropriate units.