Questions!! Need Answers (1 Viewer)

[pH|dignity]

can someone please answer the following questions... pretty plz

1. A transfromer is said to be 90% efficient. If the transformer has an input of 240 V, an output voltage of 24.5V and has an ouptut current of 2.65 A, determine the electricical energyu drawn from the power supply in 3 hours of usage.

2. Explain why an object that is 6000K appears yellow

3. A 1600kg vehicle is travelling at 14.5m/s is allowed to slow to a halt over a distance of 350m. Determine the combined total of the frictional force and the air resistance that slows the vehicle down

appreciate it~

 

[powerhouse]

1. A transfromer is said to be 90% efficient. If the transformer has an input of 240 V, an output voltage of 24.5V and has an ouptut current of 2.65 A, determine the electricical energyu drawn from the power supply in 3 hours of usage.


P(output) = 24.5 x 2.65 = 65

65 = P(input) x (9/10)

P(input) = I x 24.5

65 = I x 24.5 x (9/10)

I(input) = 29.5

So that's the input current, I'm not sure where to go from there though.

 

[Xayma]

Powerhouse, the current will be much lower, check over the voltage values you used again

Generally speaking you would be looking in the 200mA range (about 1/10 of the output current).

Power = Work/Time
So electrical energy input = power input * time

 

[helper]

1.
E_out=VIt=24.5*2.65*3*60*60=701.19KJ
E_out=%*E_in
701.19=0.9*E_in
E_in=711.1KJ

2. The peak of the black body curve is in the yellow section of the spectrum.

3.v²=u²+2as
14.5²=0+2*a*350
a=0.3 m/s
F=ma=481 N

No guarantee on maths

 

[powerhouse]

Actually it did seem a little weird when i got that answer