Physics costing electricity, KW/KWh

How long could you run a 2 kW hairdryer on 50p if electricity costs 7.5p per unit?

[Image Analyst]

This looks like a homework problem. If you have any questions ask your instructor or read the link below to get started:

How do I get help on homework questions on MATLAB Answers? - MATLAB Answers - MATLAB Central

Obviously we can't give you the full solution because you're not allowed to turn in our code as your own.

Answer 1

[VBBV]

% assume
P_rating = 2e3; % 2000 W = 2kW
number_units = 50/7.5   % since each unit is treated as 1kWh @ 7.5p per unit

number_units = 6.6667

run_time =  number_units /(P_rating/1000)  % apprx run time in hours   

run_time = 3.3333

[VBBV]

The above is true if you consider the device to operate at its rated power otherwise, there will be more possibilites.

% assume
P_rating = [1e3 2e3]; % 2000 W = 2kW  is nominal rating of device , 1e3 is power when device can work at lower speeds
number_units = 50/7.5   % since each unit is treated as 1kWh @ 7.5p per unit

number_units = 6.6667

run_time =  number_units ./(P_rating/1000)  % apprx run time in hours   

run_time = 1×2

6.6667 3.3333