Force Calculation: Help with Question 8

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To calculate the force exerted on the board by the karate master, the relevant equations are momentum and impulse, represented as mv = Ft. The change in velocity is determined by subtracting the final velocity (1 m/s) from the initial velocity (10 m/s), resulting in a change of 9 m/s. Using the mass of the hand and arm (1 kg) and the contact time (0.002 s), the force can be calculated as F = (mass * change in velocity) / time, leading to a force of 4500 N. The discussion confirms this calculation is correct, and additional resources for understanding impulse and momentum are provided.
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8. A karate master strikes a board with an initial velocity of 10 m/s, decreasing to 1 m/s as his hand passes through the board. If the time of contact with the board is 0.002 s, and the mass of the coordinated hand and arm is 1 kg, what is the force exerted on the board.

a. 1000 N
b. 1800 N
c. 2700 N
d. 4500 N

- well, I lost my book because my backpack got stolen and I have an older physics book i got from a friend and the pages don't match up with my study guide. I can't find the right equation for this. I need an equation that uses change in velocity, contact time, and mass of the object to get F in Newtons. If anyone can show me how I do this or at least point me in the right direction I would appreciate it.
 
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Momentum=Impulse

mv=Ft
 
laminar said:
Momentum=Impulse

mv=Ft

so...

m = mass
v= change in velocity?
F= force in N
t= time

is v the initial, final, or change in velocity?

if it is change in velocity, then i get:

9*1/0.002 = 4500 N

Is this right?
 
Last edited:
bump. any feedback appreciated.
 

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