Homework Help

In Chapter 4, you found that when a karate strike hits wooden blocks, the hand...

user profile pic

sarah9615 | eNotes Newbie

Posted October 21, 2013 at 8:25 PM via web

dislike 0 like

In Chapter 4, you found that when a karate strike hits wooden blocks, the hand undergoes an acceleration of -6.50e3 m/s2. Medical data indicates the mass of the forearm and hand to be about 0.700 kg. What is the force exerted on the hand by the block?

1 Answer | Add Yours

user profile pic

valentin68 | College Teacher | (Level 3) Associate Educator

Posted October 22, 2013 at 5:51 AM (Answer #1)

dislike 0 like

Newton second law states that to accelerate an object having a mass `m` with acceleration `a` one needs to apply to it an external force `F` having the value

`F =m*a`

Thus in the case shown in problem the external force value is

`F =0.7*(-6.5*10^3) =-4550 N`

The minus sign in front of the force shows that it is opposing the direction of motion of the hand.

Answer: the absolute value of the force exerted on the hand is 4550 N

Join to answer this question

Join a community of thousands of dedicated teachers and students.

Join eNotes