a 75-kg petty theif wants to escape from a third story window. unfortunately a makeshift rope of sheets tied together can support a mass of only 58 kg. how might the theif use this rope? give a quantitative answer.
2 answers
I don't have an answer but just to get you thinking maybe the thief fold the rope in half and hold onto both halves as he descends. Or the thief can apply some of his weight to the wall.
He can use it singly, if he controls his descent.
tensionallowed=mg-ma
58g=75g-75a
or a=17/75 g= 2.2m/s^2
lets see if he can safely land at the bottom...
vf^2=2*2.2*10m (using 10 m as three stories)
vf=sqrt 44 appx 7m/s. I don't think he will survive the crash with ground. So, stick with making it double.
tensionallowed=mg-ma
58g=75g-75a
or a=17/75 g= 2.2m/s^2
lets see if he can safely land at the bottom...
vf^2=2*2.2*10m (using 10 m as three stories)
vf=sqrt 44 appx 7m/s. I don't think he will survive the crash with ground. So, stick with making it double.
1 answer