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1) A person in a kayak starts paddling and it acclerates from 0 m/s to 60 m/s in

ID: 1432031 • Letter: 1

Question

1) A person in a kayak starts paddling and it acclerates from 0 m/s to 60 m/s in a distance of 0.41m. If the combined mass of the person and the kayak is 73 kg, what is the magnitude of net force acting on the kayak? *So I thought I needed to first find the acceleration by dividing it by the distance and then plugging it into F = ma but that was not corrrect. The answer I believe is 52-53 ish.

2) A boat has a mass of 6800 kg. Its engines generate a drive force of 4100 N due West while wind exerts a force of 800 N due East and the water exerts a resistive force of 1200 N due East. What are the magnitude and direction of the boat's acceleration? *I summed the forces and then plugged into F = ma and got an acceleration of -0.31 m/s^2. Just need someone to check me!!*

Thank you!!

Explanation / Answer

a) s = 0.41m
Assuming constant acc.
2as = v^2 - u^2
a = 60^2/2*0.41 = 4390.2439 m/s/s
F= ma = 320487.8048 N

b) m = 6800 kg
Fw = 4100N
Fe = 800N
Fr = 1200N (east)
Net F in West = 4100N
Net F in east = 2000N
Magnitude of F = 2100 N
Maagnitude of acc = F/m = 0.30882 m/s^2
Direction = West