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

In a floor there is a heavy duty uniform trap door that is hinged at one side the door has a mass if M = 25 kg a length from hinge to edge of L = 1.0 m, and rotational moment of inertia I = (ML^2)/3= 8.33 kg*m^2.

Question 1:

What upward Force must be applied to handle at the edge of the door in order to hold it stationary with an angle of 60 with respect to the floor?

Question 2:

The door released and allowed to swing closed. immediately after release what is the angular acceleration of the door?

Question 3:

What angular velocity does the door have just before it slams shut?

The Attempt at a solution

for question 1:

T= r.m.g.sin(@)

= 0.5 m x 25 kg x 9.8 m/s^2 x sin 60

= 106.09 N.m

for question 2:

T= I.alfa

106.09 = 8.33 . alfa

alfa = 12.74 m/s^2

I really dont know how to do the question 3.

is this seems ok so far to you. thanks.

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

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!

# Homework Help: Torque Problem. Need Help

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