PHYS1001 Help.

[nml10]

I was working on MasteringPhysics, due tomorrow 7pm and I was not able to solve these two questions.. PLEASE HELP! D:

1) While exploring a castle, Exena the Exterminator is spotted by a dragon who chases her down a hallway. Exena runs into a room and attempts to swing the heavy door shut before the dragon gets her. The door is initially perpendicular to the wall, so it must be turned through to close. The door has a height of2.95 <nobr></nobr>and a width of 1.10 , and its weight is 720 . You can ignore the friction at the hinges.

If Exena applies a force of 250 at the edge of the door and perpendicular to it, how much time does it take her to close the door? (Use 9.80 for the acceleration due to gravity.)

2) This applet shows the results of releasing a frictionless block and a rolling disk with equal masses from the top of identical inclined planes. (The applet compares a circular object and a rectangular object sliding down the same inclined plane where the rectangular object slides down quicker than the circular one)

How much sooner does the box reach the bottom of the incline than the disk?
Express your answer in terms of some or all of the variables , , , and , as well as the acceleration due to gravity .

[wawawewa]

lol i remember this question... you have to post up the hints for the disk one for me to be able to do it

[jet]

Try to do the question first, and post up your solution. Then we'll give you hints, but we aren't just going to do assignment questions for you.

[Riproot]

They're both pretty simple if you look at mike wheatland's lecture notes (D)

That's how I solved it.


I'm having trouble with questions 2-4. :/

[nml10]

i went through the lecture notes and textbook and got the two questions