{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

exam3_2004S_sol

# exam3_2004S_sol - Mark answers in spaces 53-75 on the...

This preview shows pages 1–4. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
[54] What is the x-component of the angular momentum about the origin of a particle located at the point m j r ) ˆ 2 ( = G with mass 2kg and a velocity of s m k j i v / ) ˆ 3 ˆ 2 ˆ ( + + = G Angular momentum is given by s m kg s m k j i m j kg v m r L / 12 / ) ˆ 3 ˆ 2 ˆ )( ˆ 2 )( 2 ( 2 + = + + = × = G G G Correct response=44% The most popular wrong answer was A which I guess results from forgetting to multiply by the mass.
[55] Three balls are rolled down an incline ramp and roll without slipping. Ball X is a solid ball of radius 5cm and mass 1kg. Ball Y is another solid ball of radius 10cm and mass 0.5kg. Ball Z is a hollow ball of radius 5cm and mass 1kg. Neglecting drag, kinetic and rolling friction, if these three balls are released simultaneously from the top of the ramp, in which order do they arrive at the bottom? As these balls roll down the ramp, they should undergo uniform acceleration so that if v f is the final velocity at the bottom of the ramp and L is the length of the ramp, the time to get to the bottom is: f v L t / 2 = Thus, the ordering of the objects is the objects in time is the reverse of the ordering in terms of final velocity. The fastest final velocity is the ball which gets to the bottom first (hopefully this intuitively obvious). The problem is thus reduced to determining the velocity of the balls at the bottom of the ramp. Consider now a ball of radius r, moment of inertia I and mass m. Denote the height of the ramp by h. The total kinetic energy which the ball will have at the bottom of the ramp will be K=mgh.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
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