After a heavy snowfall, Annie wants to drag a sled loaded withtoys across her level backyard floor, by pulling a rope at an angleof 26 degrees up from the snowy floor. When Annie increases herpull to 25N, the sled starts. Two days later, all the snow hasmelted leaving the concrete exposed. Annie pulls on the loadedsled, but now it has become harder to get it to start. Annie doesnot want to change the pulling angle, because it is most naturalfor her. Answer the 3 parts:
a) Draw a free body diagram for Annie's sled, labelingforces
b) The coefficients of static friction for snow and concrete are0.15 and 0.95, respectively. How large is the normal force of thefloor in the two cases (snow and concrete)?
c) How much mass does Annie need to remove from the sled, to beable to start the sled on the concrete by pulling just as hard asshe did earlier on the snow?
