The chewing muscle, the masseter, is one of the strongest in the human body. It is attached to the mandible (lower jawbone) as s
hown in figure
(A) The jawbone is pivoted about a socket just in front of the auditory canal. The forces acting on the jawbone are equivalent to those acting on the curved bar in figure
(B) In figure a, a skull is shown. The lower jaw is labeled "Mandible".
A muscle labeled "Masseter" connects the back of the lower jaw to the upper part of the skull. In figure b, The jawbone is modeled by a curved bar. The left portion of the bar is horizontal, the right portion bends diagonally up and to the right. Three forces act on the bar: Vector T points directly upward at the point where the bar bends. Vector FC acts directly downward at the left end of the bar, a horizontal distance of 7.50 cm from vector T. Vector T points directly upward at the point where the bar bends. Vector R acts directly downward at the right end of the bar, a horizontal distance of 3.50 cm from vector T. F C is the force exerted by the food being chewed against the jawbone, T is the force of tension in the masseter, and R is the force exerted by the socket on the mandible. Find T and R (in N) for a person who bites down on a piece of steak with a force of 56.6 N. magnitude of R N
(A) The jawbone is pivoted about a socket just in front of the auditory canal. The forces acting on the jawbone are equivalent to those acting on the curved bar in figure
(B) In figure a, a skull is shown. The lower jaw is labeled "Mandible".
A muscle labeled "Masseter" connects the back of the lower jaw to the upper part of the skull. In figure b, The jawbone is modeled by a curved bar. The left portion of the bar is horizontal, the right portion bends diagonally up and to the right. Three forces act on the bar: Vector T points directly upward at the point where the bar bends. Vector FC acts directly downward at the left end of the bar, a horizontal distance of 7.50 cm from vector T. Vector T points directly upward at the point where the bar bends. Vector R acts directly downward at the right end of the bar, a horizontal distance of 3.50 cm from vector T. F C is the force exerted by the food being chewed against the jawbone, T is the force of tension in the masseter, and R is the force exerted by the socket on the mandible. Find T and R (in N) for a person who bites down on a piece of steak with a force of 56.6 N. magnitude of R N
1 answer:
You might be interested in
(a) +2.60 m/s
The motion of the fish dropped by the seagul is a projectile motion, which consists of two independent motions:
- a horizontal uniform motion, at constant speed
- a vertical motion, at constant acceleration (acceleration of gravity, , downward)
In this part we are only interested in the horizontal motion. As we said the horizontal component of the fish's velocity does not change, therefore its value when the fish reaches the ocean is equal to its initial value, which is the speed at which the seagull was flying (because it was flying horizontally):
(b) -17.2 m/s
The vertical component of the fish's velocity instead follows the equation:
where
is the initial vertical velocity, which is zero
is the acceleration of gravity
t is the time
Since the fish reaches the ocean at t = 1.75 s, we can substitute this time into the formula to find the final vertical velocity:
where the negative sign indicates the direction (downward).
(c)
The horizontal component of the fish's velocity would increase
The vertical component of the fish's velocity would stay the same.
As we said from part (a) and (b):
- The horizontal component of the fish's velocity is constant during the motion and it is equal to the initial velocity of the seagull -> so if the seagull's initial speed increases, the horizontal velocity of the fish will increase too
- The vertical component of the fish's velocity does not depend on the original speed of the seagull, therefore it is not affected.