# 4 a toy rocket is initially traveling at 10ms in the

This preview shows page 1. Sign up to view the full content.

4. A toy rocket is initially traveling at 10m/s in the x direction (denoted by the unit vector i ) when it explodes into 4 pieces in air. The four pieces have mass m 1 =m 3 =2kg, m 2 = 5kg, m 4 =1kg, the masses m 1 , m 2 , m 3 are observed to have v 1 =2 i , v 2 = -4 i + 2 j , v 3 =2 j . What is the velocity and speed of the fourth mass as measured by an observer at rest? 5. Consider a massless door with a doorknob of mass 3kg. If the distance from the hinge to the doorknob is .5m and you push the door open with a force of 10 N directed 30 degrees behind the door (where 90 degrees behind the door would be perpendicular to the door and 0 degrees behind the door would be along the line that connects the hinge to the doorknob) what is the instantaneous angular acceleration of the doorknob about the hinge? 6. A block of mass m travels around a large hoop of radius R at in uniform circular motion (UCM) as shown in the figure. a) Write down an expression for the Normal force in terms of m, g, theta, and the velocity and radius of UCM. b) The block hits a rough patch where there is friction with coefficient u. The tangential momentum of the block is defined as the momentum along the direction of the hoop. Write down a differential equation for the tangential momentum of the block in terms of m, g, u, and theta.
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern