A boy of mass 60.0 kg is rescued from a hotel fire by leapinginto a firefighters
ID: 1722161 • Letter: A
Question
A boy of mass 60.0 kg is rescued from a hotel fire by leapinginto a firefighters' net. The window from which he leapt was 8.0 mabove the net. The firefighters lower their arms as he lands in thenet so that he is brought to a complete stop in a time of 0.40s. a) What is his change in momentum during the 0.40 sinterval? b) What is the impulse on the net due to the boy during theinterval? [Hint: Do not ignore gravity.] c) What is the average force on the net due to the boy duringthe interval? A boy of mass 60.0 kg is rescued from a hotel fire by leapinginto a firefighters' net. The window from which he leapt was 8.0 mabove the net. The firefighters lower their arms as he lands in thenet so that he is brought to a complete stop in a time of 0.40s. a) What is his change in momentum during the 0.40 sinterval? b) What is the impulse on the net due to the boy during theinterval? [Hint: Do not ignore gravity.] c) What is the average force on the net due to the boy duringthe interval?Explanation / Answer
Given that mass m = 60.0 kg h = 8.0 m t = 0.40s --------------------------------------- We know that v2- u2 = 2gh Here u =0 v =(2gh) So u = -v and u =0 a) The change in momentum during the 0.40 sinterval is P = m (v -u) = m ((2gh)) b) The impulse on the net = change inmomentum = m ((2gh)) c) The average force on the net due tothe boy during the interval is F = P/t Substitute the values.Related Questions
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