Question

I NEED HELP PLEASE THANKS! :)

While doing bicep curls, Tamara applies 155 Newtons of force to lift the dumbbell. Her forearm is 0.366 meters long and she begins the bicep curl with her elbow bent at a 15° angle below the horizontal, in the direction of the positive x-axis. Determine the magnitude of the torque about her elbow.
(Show work)

Answer 1

55

Explanation:

Tamara's forearm is given to be 0.366 meters in length, so that a force of 155 newtons is being applied at this distance from her elbow. Again, this force is applied at an angle of 15 degrees, so that the positioning should be the following -

r = ( 0.366( cos 15 ), 0, 0.366( sin 15 ) ),

r = ( 0.35352885242, 0, - 0.0947277705 ) - ( Approximately )

Now the force is applied in the vertical direction, so -

F = ( 0, 0, 155 )

_________________________________________________

We can now multiply the two ( ( 0.35352885242, 0, - 0.0947277705 ) and ( 0, 0, 155 ) ), performing the following calculation to receive " j " the magnitude,

`|0.35352885242, 0, - 0.0947277705 |\\* | 0, 0, 155 |,\\\\( 0( 155 ) - 0( - 0.0947277705 ) ) - ( 0.35352885242( 155 ) - 0( - 0.0947277705 ) ) + ( 0( 0.35352885242 ) - 0( 0 ) )\\\\Solution = ( 0, ( About ) 54.8, 0 )`

And as you can see, j / magnitude is about 54.8