The figure below shows a clawhammer as it is being used to pull a nail out of a horizontal board. A force of magnitude 130 N is exerted horizontally as shown. (NOTE: Assume that the force the hammer exerts on the nail is parallel to the nail and perpendicular to the position vector from the point of contact. The x-component of this force's lever arm is 5 cm.)

Question

(a) Find the force exerted by the hammer claws on the nail.

(b) Find the force exerted by the surface at the point of contact with the hammer head.

webassign(dot)net/sercp9/8-p-068(dot)gif

Answer 1

Isn't this just a leaver mechanical advantage issue?

Answer 2

Yes. Still need help figuring out the forces exerted though.

Answer 3

The instructor wants us to use the sum of the torques to figure out the problem.

Answer 4

The web address is posted below my question if you would like to see the picture. The (dot)=.

Answer 5

measure the distance from the hand to the fulcrum, and the distance from the fulcrum to the nail.

Forcehand*distancehandToF=forcenail*distancenailtoF.

Why is this so? The same amount of work is done on each end. Work=forceapplied*distancemoved thru.

However, the distance the force moves through is directly proportional to the distance to the handle fulcurm (thnk on that).

Answer 6

work=torque*angle displacement

now proved by similar triangles the angle displacements are the same on the claw, and the handle. Leaving you with my force*distancetofulcrum argument above.

Answer 7

Thank you very much. That makes sense. I will apply that reasoning.

Answer 8

Did you examine the picture? There are angles involved. The nail is at a 30 degree angle in the wood.

Answer 9

No, didn't see the picture. You take care of that in the torque, sine of the angle between force and the object direction.