IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => GCE AS & A2 Level => Sciences => Topic started by: mousa on November 29, 2009, 02:14:28 pm

Title: Mechanics Question!!
Post by: mousa on November 29, 2009, 02:14:28 pm

hey everyone.. well i got stuck on a cie mechanics question.. it soundzz simple( the question).. but i dunno why i am getting stuck on it!! well ,  here is the question :)

A shopper picks up a 2Kg packet of  rice with the thumb and index finger of one hand .The coefficient of friction between her fingers and the wrapping is 0.3. What horizontal force must she exert to prevent the packet from slipping!

help!!

Title: Re: Mechanics Question!!
Post by: astarmathsandphysics on November 29, 2009, 02:58:56 pm

2g/2*0.3=g/0.3

Title: Re: Mechanics Question!!
Post by: spiderman on November 30, 2009, 12:27:30 pm

Hey Mousa,
heres the answer to ur question........

Limiting friction= mew * 2N(2times normal contact foce as she is using 2 fingers)
20 = 0.3*2N
20/0.3=2N
2N=66.67
N=33.33N
Hence the horizontal force she needs to apply to prevent the rice fromslipping is 33.33N

Hope this helped.........