Recent content by lmc489

Homework Statement Two disks with moments of inertia I and 31 are mounted on a common shaft with frictionless bearings. They are initially rotating with angular speeds of w and 2w. They are brought together without being disturbed. What is their final KE as a fraction of their initial KE...

oh YES! i forgot. so instead the answer would be 200 right?

Homework Statement A disk is rotating freely at 1,000 revolutions per minute about a vertical axis through its center. A hoop with twice the mass of the disk and the same radius as the uniform disk is poised exactly above and is initially at rest. The hop is dropped gently upon the disk so...

so how would i go about finding the expression for the bullet's speed?

I would think that the block is going to far enough that the spring compresses right??

Homework Statement You have been asked to design a "ballistic spring system" to measure the speed of bullets. A spring whose spring constant is k is suspended from the ceiling. A block of mass M hangs from the spring. A bullet of mass m is fired vertically upward into the bottom of the...

A .3 kg ball is dropped from a height of 2 m. It strikes the group and rebounds to a height of 1.5 m. The collision with the ground lasts for .01 seconds. The average force exerted by the ground on the ball is: a)280 b) 540 c) 430 d) 350 So, i know that we have to use some type of...

Two wires are tied to the 200 g sphere shown in figure. The sphere revolves in a horiIzontal circle at a constant speed of 7.80 m/s. The diagram shows a ball with two wires, each 1 m in length with a radius of .5 m What is the tension in the upper wire? What is the tension in the lower...

i got it! thank you!

nevermind! i got it!

uk=F/N F=mg F=mw^2r mw^2r=N uk=F/N (30kg)(w^2)(2.45m)=30g/.4 somehow i don't think I am getting the right answer though... i get like 1.01 rad/s but i don't think that's right?

The weight of passengers on a roller coaster increases by 50 % as the car goes through a dip with a 36 m radius of curvature. What is the car's speed at the bottom of the dip? Do you use the equation mv^2/r ?? how would you go about doing this problem?

so how do you do this problem?

In an old-fashioned amusement park ride, passengers stand inside a 4.9-m-diameter hollow steel cylinder with their backs against the wall. The cylinder begins to rotate about a vertical axis. Then the floor on which the passengers are standing suddenly drops away! If all goes well, the...