Copyright © Michael Richmond.
This work is licensed under a Creative Commons License.
Question 1:
Professor Plum drags a coffin across the floor at constant velocity, using a rope which he pulls at an angle of 20 degrees above the horizontal. The coffin has mass 120 kg. The coefficient of kinetic friction between coffin and floor is 0.3.
Draw a picture of all the forces acting on the coffin.
Answer:
normal force
^ tension
| /
/
-------------- /
| | /
friction <--- | | /
| |
--------------
|
v
gravity
Make a table, listing the x and y components of each force.
Answer: x y
------------------------------------------------------------
gravity 0 - (120 kg)(9.8 m/s^2)
normal force 0 + Fn
friction - (0.3)*Fn 0
tension + T cos(20) + T sin(20)
=======================================
total force 0 0
Copyright © Michael Richmond.
This work is licensed under a Creative Commons License.