A battery-powered winch is used to lift a load.
The potential difference across the motor in the winch is 12 V and the current in the motor is 2.5 A.
The winch takes 8.0 s to lift the load.
In this time, the gravitational potential energy store of the load increases by 180 J.
Calculate the energy transferred to the motor.
Use the equation
energy transferred=current×potential difference×time\text{energy transferred} = \text{current} \times \text{potential difference} \times \text{time}energy transferred=current×potential difference×time
Calculate the energy dissipated while the load is lifted.
Calculate the rate at which energy is dissipated.
All of the dissipated energy is transferred by the current heating the wire in the coil of the motor.
Calculate the resistance of the coil.
Describe the changes in energy stores that take place while the load is being lifted.
105 exam-style questions on Edexcel GCSE Physics 10.3 Electrical energy and power, covering 10.3.1 The heating effect of an electric current, 10.3.2 Reducing energy transfer in wires, 10.3.3 Advantages and disadvantages of the heating effect, 10.3.4 Energy transferred by an electrical circuit, 10.3.5 Electrical power, and 10.3.6 Energy transfers in domestic devices. Each one has a worked solution and a mark scheme showing where the marks go.