Physics 113 –Morning 2006

Extra credits problems #2

Team #______________

Member 1__________________

Member 2__________________

Member 3__________________

Rules:

-Collaboration between team members is encouraged; however one or two members will be responsible for one problem and may be asked to explain it.

-The author members should present the solution on a blank sheet with their names on it

-Solutions should include “self-explained” diagrams/sketches, with minimal wording, and clearly written equations. Neat presentation will count toward the problem grading.

1.- Design a method to calculate the force your hand exerts on a 10g coin if the hand/coin contact time is 0.3s, by using only a stopwatch.

2.- Three masses (2kg, 3kg, 5kg, from left to right) are connected on a horizontal frictionless surface via massless springs with k=100N/m. A 20N is applied on the rightmost mass. What are the springs’ displacements?

3.- You step into an elevator, it accelerates and during 2s you feel your weight is only half of the normal weight. What is the direction and magnitude of the elevator’s velocity?