89204
Descrição
FlashCards por Lewis White, atualizado more than 1 year ago
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Criado por Lewis White
mais de 11 anos atrás
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| Questão | Responda |
| A 1 kilogram brick is carried up the Eiffel Tower to the 275m platform. How much gravitational potential energy does the brick gain? | E=mgh |
| A 1000 kilogram car has a kinetic energy of 12500J. Calculate the speed the car is moving at. | E=1/2m(vxv) |
| An electrical motor rated at 12V and 0.2A is used to lift a 500g mass up a height. If the motor is switched on for 5 seconds calculate how far the mass is lifted. | E=mgh |
| A 2kW electric kettle is used to heat water. After 5 minutes the heat energy in the water is measured to be 450kJ. Calculate the efficiency of the kettle. | %Efficiency=(Eout)/(Ein)x100 |
| How much energy must be transfered to raise the tempreture of 2kg of water from 20 degrees C to 30 degrees C? | E=cmDeltaT |
| Calculate the final tempreture of 3kg of lead which has been heated by an electrical heater of power 0.1kW for 2 minutes. The initial tempreture of the lead is 20 degrees C. Assume that no heat energy is lost t the atmosphere | E=Pt then (assuing it is 100% efficient) E=cmdeltaT |
| Calculate how much heat energy is needed to turn 2kg block of ice at minus 5 degrees C into water at 50 degrees C. Assume there are no losses of heat energy to the atmosphere. | E=cmdeltaT then E=mL then E=cmdeltaT |
| The pressure of a gas enclosed in a cylinder by a piston changes from 80kPa to 200kPa. If there is no change in tempreture and the initial volume was 25 litres, calculate the new volume | P1V1=P2V2 |
| The pressure of a gas enclosed in a cylinder is 180kPa at a temperature of 27 degrees C. If it is heated to a tempreture of 77 degrees C, calculate the new pressure. | P1/T1=P2/T2 |
| The volume of a weather balloon that travels to extreme heights is 1(mxmxm) at sea level where the temperature is 21 degrees C. Calculate the new volume of the balloon when it rises to a height of 10km where the temperature is minus 45 degrees C | V1/T1=V2/T2 |
| An electric fan has a resistance of 100 Ohms and is plugges into a wall outlet. How much current runs through the fan? | V=IR |
| The gas container which allows the volume to change store helium of volume 1.5(mxmxm) at a pressure of 100kPa and a temperature of 27 degrees C. If the pressure is increased to 250kPa at a temperature of 127 degrees C, calculate the new volume of the container. | P1V1/T1=P2V2/T2 |
| An electrical mains heater is switched off for a period of 2 hours. If the heating elements operate at a current of 8A, find the electrical energy produced by the heater | P=IV then E=Pt |
| Calculate the resistance of the element in a 2kW mains operated electrical heater. (Note: the 'element' is the name given to the section of wire that heats up when the current flows through it). | (VxV)=PR |
| Calculate the number of units of electricity used by a 60W bulb that is kept switched on for 8 hours and 45 minutes. We need to find the number of kWh | E=Pt |
| The weightlifter lifts the barbell at a constant speed from the ground up to the height shown in a time of 4 seconds | W=mg then E=Fd then E=Pt |
| Calculate the total charge which flows through a cell in 2 minutes when the current in the circuit is 5A | Q=It |
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