a catcher picks up a baseball from the ground, if the unbalanced force on the ball is 7.25 x 10^-2 N and 4.35 x 10^-2 J of work
1 answer:
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Ans:
1. τbiceps = +(Positive)
2. τforearm = -(Negative)
3. τball = -(Negative)
Explanation:
The figure is attached down below.
1. T<span>orque about the elbow caused by the biceps, τbiceps:
Since Torque = r x F (where r and F are the vectors)
</span>Where r is the vector from elbow to the biceps.
<span>
We can see in the figure that F(biceps) is in upward direction, and by applying the right hand rule from r to F, we get the counterclockwise direction. The torque in counterclockwise direction is positive(+). Therefore, the sign would be +.
2. </span>Torque about the the weight of the forearm, τforearm:
Since Torque = r x F (where r and F are the vectors)
Where r is the vector from elbow to the forearm.
Also weight is the special kind of Force caused by the gravity.
We can see in the figure that W(forearm) is in downward direction, and by applying the right hand rule from r to F, we get the clockwise direction. The torque in clockwise direction is negative(-). Therefore, the sign would be -.
3. Torque about the the weight of the ball, τball:
Since Torque = r x F (where r and F are the vectors)
Where r is the vector from elbow to the ball.
Also weight is the special kind of Force caused by the gravity.
We can see in the figure that W(ball) is in downward direction, and by applying the right hand rule from r to F, we get the clockwise direction. The torque in clockwise direction is negative(-). Therefore, the sign would be -.
1. τbiceps = +(Positive)
2. τforearm = -(Negative)
3. τball = -(Negative)
Explanation:
The figure is attached down below.
1. T<span>orque about the elbow caused by the biceps, τbiceps:
Since Torque = r x F (where r and F are the vectors)
</span>Where r is the vector from elbow to the biceps.
<span>
We can see in the figure that F(biceps) is in upward direction, and by applying the right hand rule from r to F, we get the counterclockwise direction. The torque in counterclockwise direction is positive(+). Therefore, the sign would be +.
2. </span>Torque about the the weight of the forearm, τforearm:
Since Torque = r x F (where r and F are the vectors)
Where r is the vector from elbow to the forearm.
Also weight is the special kind of Force caused by the gravity.
We can see in the figure that W(forearm) is in downward direction, and by applying the right hand rule from r to F, we get the clockwise direction. The torque in clockwise direction is negative(-). Therefore, the sign would be -.
3. Torque about the the weight of the ball, τball:
Since Torque = r x F (where r and F are the vectors)
Where r is the vector from elbow to the ball.
Also weight is the special kind of Force caused by the gravity.
We can see in the figure that W(ball) is in downward direction, and by applying the right hand rule from r to F, we get the clockwise direction. The torque in clockwise direction is negative(-). Therefore, the sign would be -.
The ball was dropped from a height 20 meters
Explanation:
The given is
1. A ball is dropped from the top of a cliff
2. By the time it reaches the ground, all the energy in its gravitational
potential energy store has been transferred into its kinetic energy
store, that mean K.E = P.E
3. The ball is travelling at 20 m/s when it hits the ground
4. The gravitational field strength is 10 N/kg
We need to find the height that the ball dropped from it
The ball dropped from the top of a cliff means the initial speed is 0
→ K.E =
where v is the final speed, in the initial speed and m
is the mass
→ v = 20 m/s and = 0 m/s
→ K.E =
→ K.E =
→ K.E = 200 m joules ⇒ when the ball hits the ground
→ P.E = m g h
where g is the gravitational field strength, m is the mass and h is
the height
→ g = 10 N/kg
→ P.E = m(10)(h)
→ P.E = 10 m h joules
→ P.E = K.E
→ 10 m h = 200 m
Divide both sides by 10 m
→ h = 20 meters
The ball was dropped from a height 20 meters
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Answer: (A) velocity = 2.8m/s
(B) Average force = 1.9536 Newtons
Explanation:
Find detailed explanation in the attached picture
