Recent content by shell4987

Homework Statement Figure 11-45 shows a rigid structure consisting of a circular hoop of radius R and mass m, and a square made of four thin bars, each of length R and mass m. The rigid structure rotates at a constant speed about a vertical axis, with a period of rotation of 2.8 s. Assuming R...

Force is Force = (8.7 N)i - (4.2 N)k and position vector = (3.7 m)j - (6.5 m)k, which is relative to the origin

Homework Statement Force = (8.7 N) - (4.2 N) acts on a pebble with position vector = (3.7 m) - (6.5 m), relative to the origin. What is the resulting torque acting on the pebble about (a) the origin and (b) a point with coordinates (5.0 m, 0, -1.7 m)? Homework Equations The cross...

Homework Statement A disk rotates about its central axis starting from rest and accelerates with constant angular acceleration. At one time it is rotating at 7.0 rev/s; 83 revolutions later, its angular speed is 18 rev/s. Calculate (a) the angular acceleration (rev/s^2), (b) the time required...

For (a) I got 1.75seconds and for (b) I got 2.48 seconds. I used 2.53 as the first displacement and for w I put in 0 and for acceleration I put 1.65 and then solved for t and that's what I got, and for the second part I put in 5.06 for the displacement. What am I doing wrong?

theta-theta initial= w initial(t) + (1/2)at^2?

Homework Statement A merry-go-round rotates from rest with an angular acceleration of 1.65 rad/s2. How long does it take to rotate through (a) the first 2.53 rev and (b) the next 2.53 rev? Homework Equations The Attempt at a Solution I tried to do this and I converted the rev to...

Momentum?

Mass is conserved in this explosion but it's in two different forms.

Homework Statement An object, with mass 79 kg and speed 23 m/s relative to an observer, explodes into two pieces, one 5 times as massive as the other; the explosion takes place in deep space. The less massive piece stops relative to the observer. How much kinetic energy is added to the system...

Okay, I found the xcom to be 0.108 and the ycom to be 1.288, but I don't know how to do part 2 because what equation do I use that involves force and time?

A big olive (m = 0.15 kg) lies at the origin of an xy coordinate system, and a big Brazil nut (M = 0.46 kg) lies at the point (0.72, 2.8) m. At t = 0, a force o = (1 + 1) N begins to act on the olive, and a force n = (-2 -4) N begins to act on the nut. What is the (a)x and (b)y displacement of...

what's unknown is the ycom and the xcom... so i put my information in that equation and solved it and got xcom= -0.593 and ycom=0.0767 and they are wrong. i have no idea what I'm doing wrong here.

Now I'm confused which two equations do I use? xcom=(m1x1+m2x2)/M and...?

How do I find the coordinates of the center of mass if they already gave them to me though? I now know what equation to use but I don't know how to apply it to this problem.