(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A 72 kg man jumps

a) If the jump results in an upward speed of 2.1 m/s, what additional upward force does the floor exert, if the person pushes the ground for 0.36 s?

2. Relevant equations

F= mv/t

3. The attempt at a solution

F_net = Impule/t

F_byFloor - W = F_net

f_byFloor = F_net + W

= (mv_f / t) + mg

= m ((v_f / t)+g)

= 1126.32 N

But, the answer in the book is 420 N, and it just ignored Weight of the person.

If my Force equation (F_byFloor - W = F_net) is right?

1. The problem statement, all variables and given/known data

A bee lands on one end of a floating 4.75 g Popsicle stick. After sitting at rest for a moment, it runs towards the other end with a speed of 3.80 cm/s relative to still water. The stick moves in the opposite direction at 0.12 cm/s relative to the still water. What is the mass of bee?

2. Relevant equations

mv_b + Mv_popsicle = 0

3. The attempt at a solution

I am confused about the velocities. Like, How the results would be changed if I use bee velocity relative to Popsicle. And, do I need to have velocities of both objects relative to some stationary thing in order to solve this problem?

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# Homework Help: Two momentum questions

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