The following pairs of surfaces are pushed together with the same amount of force. between which pair of surfaces will friction be the greatest?
a. two pieces of sandpaper
b. two pieces of waxed paper
c. a painted surface and a piece of sandpaper
d. a painted surface and a piece of waxed paper

juan and his friends want to build their own go-karts and race down their street. according to newton’s second law of motion, which of these will juan to win the race?
a. increasing the mass of his go-kart
b. increasing the amount of inertia the go-kart has
c. decreasing the net force applied to the go-kart
d. decreasing the mass of his go-kart

1. how much energy is needed to raise the temperature of 40.0 g of argon from 25c to 40c? the specific heat capacity of argon is 0.520 j/(g·k) 2a. 23.0 ml of 0.100 m hcl (standard) are added from a buret to neutralize 50.0 ml of an unknown basic solution. 2b. if the oh- produced in the previous reaction came from ca(oh)2, then what is the molarity of the ca(oh)2? 3.calculate the new freezing-point of a solution when 60.5 grams of cacl2 solute is dissolved in 0.612 kg of water. 4. what is the maximum number of moles of alcl3 that can be produced from 5.0 mol al and 6.0 mol cl2? 5. a sample of oxygen gas has a volume of 150 ml when its pressure is 0.923 atm. if the pressure is increased to 0.987 atm and the temperature remains constant, what will the new volume be? 6. nitrogen gas in a closed container at a temperature of 100.0 oc and 3.0 atm is heated to 300 oc. what is the pressure of the gas at the higher temperature?