Un fir de cauciuc de lungimea 1 m si sectiunea 10mm patrati se alungeste acu 1 cm ce marime are forta de deformare

The 5-kg cylinder is initially at rest when it is placed in contact with the wall b and the rotor at a. if the rotor always maintains a constant clockwise angular velocity v = 6 rad> s, determine the initial angular acceleration of the cylinder. the coefficient of kinetic friction at the contacting surfaces b and c is mk = 0.2.

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?

Aheat engine running backward is called a refrigerator if its purpose is to extract heat from a cold reservoir. the same engine running backward is called a heat pump if its purpose is to exhaust warm air into the hot reservoir. heat pumps are widely used for home heating. you can think of a heat pump as a refrigerator that is cooling the already cold outdoors and, with its exhaust heat qh, warming the indoors. perhaps this seems a little silly, but consider the following. electricity can be directly used to heat a home by passing an electric current through a heating coil. this is a direct, 100% conversion of work to heat. that is, 19.0 \rm kw of electric power (generated by doing work at the rate 19.0 kj/s at the power plant) produces heat energy inside the home at a rate of 19.0 kj/s. suppose that the neighbor's home has a heat pump with a coefficient of performance of 4.00, a realistic value. note: with a refrigerator, "what you get" is heat removed. but with a heat pump, "what you get" is heat delivered. so the coefficient of performance of a heat pump is k=qh/win. an average price for electricity is about 40 mj per dollar. a furnace or heat pump will run typically 200 hours per month during the winter. what does one month's heating cost in the home with a 16.0 kw electric heater? what does one month's heating cost in the home of a neighbor who uses a heat pump to provide the same amount of heating?