Need help with these physics questions

[opto1422]

---

Members don't see this ad.

I'm not sure how to do these questions. Any help will be appreciated.

1. Atmospheric pressure is very nearly 100 kPA. A sealed container of air at 1 atm has a door 1m wide and 2m high. This door is very hard to open during HIGH pressure days. If the atmospheric pressure on the outside of the container is just 1% greater than on the inside, then what added force in N is required to open the container door? (answer: 2.000)

2. A 12 volt battery with an internal resistance of 1 ohm resistor. Which of the following is the current in amperes that flows in the circuit. (answer: 3)

 

[Meeehai]

These seem very familiar.

1. We know pressure is equal to F/A; we can rearrange the formula to find the force required (F = PA). We need to determine the pressure exerted against the door and the area of the door.

Atmospheric pressure is 100 kPa OR 100,000 Pa. The problem states that the pressure exerted on the outside of the door is 1% greater than on the inside. 1% of 100,000 Pa is 1000 Pa. This is the pressure exerted on the door.

Area of the door is 1m x 2m = 2 m^2

F = PA = (1000 Pa)(2 m^2) = 2000 N


2. The answer is 12 A, not 3 A. Kaplan made a mistake. I = V/R to find answer.

 

[opto1422]

Ahh thank you so much ! That boosted by physics score!