(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

You need to open a heavy door that's 30 inches wide. Instictively, you push near the edge that's farthest from the hinges. If, instead, you had pushed at a point only 10 inches in from the hinges, how much harder would you have had to push to open the door at the same speed? Explain your answer.

2. Relevant equations

Here is my attempt at the problem below. I don't know where I'm making my mistake. Any help would be appreciated. Thanks.

3. The attempt at a solution

30 inches= .76 m

Mass of Door-14 kg

I=1/3 (14kg)(.25)2 Rotational Inertia

1/3(14)(.063) I=1/3M/2

1/3(.88) I=1/3 (14kg) (.58)

.29 1/3 (8.12)

2.7

2.7/.29=9.3

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Rotations and Torque

**Physics Forums | Science Articles, Homework Help, Discussion**