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an adventurous camper (71 kg) finds him/her self stranded in the middle of a fro

ID: 1371346 • Letter: A

Question

an adventurous camper (71 kg) finds him/her self stranded in the middle of a frozen lake (diameter = 1.3 km) with only a bag of rocks (total mass 10.0 kg). The ice is so slippery, that they move about the lake's surface without friction (don't ask me how they got there in the first place). Remembering what they learned in a physics lab, they devise a way to get themselves to the edge of the lake by throwing the bag of rocks in the opposite direction of the shore with a velocity of 6.0 m/s. If they throw the rocks all at once, how long does it take for them to slide to shore?

Explanation / Answer

using momentum conservation,


(75 + 14) x 0 = 75v + 14 x 5

v =- 0.933 m/s


R = 1.1/2 km = 550 m


t = d/v =589.50 sec