Ahair dryer with a resistance of 9.6 ohms operates at 120 volts for 2.5 minutes. the total electrical energy used by the dryer during this time interval is

Explanation:

First of all, we have to find the power used by the hair dryer, which is given by

where

V = 120 V is the voltage

is the resistance of the hair dryer

Substituting,

Now we can find the total electrical energy used, given by

where P is the power and

t = 2.5 min = 150 s is the time

Substituting,

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.