Answer:12.8 ft/s
Explanation:
Given
Speed of hoop
height of top
Initial energy at bottom is
Where m=mass of hoop
I=moment of inertia of hoop
=angular velocity
for pure rolling
Energy required to reach at top
Thus 512.2 m is converted energy is spent to raise the potential energy of hoop and remaining is in the form of kinetic and rotational energy
Therefore
Answer:
The resultant electric force is 14.8N to the right.
Explanation:
Since the three charges aren't in the same line, we have to break down the force in components. First, we need to know the distance from the third charge to the other ones. That is made using the Pythagorean Theorem. As the figure is symmetric with respect to the x-axis, the two distances are the same:
Now, we use the Coulomb's Law to obtain the magnitude of the individual forces caused by each charge on the third charge:
For the same reason the distances are the same, the magnitude of the forces are the same:
So, to get the resultant force, we have to break down this forces in components. To do this, we need their angles with respect to the x-axis. Let θ₁ and θ₂ be these angles, respectively. Then, we calculate them using trigonometry:
Now, we calculate the components of the forces:
Evidently, the y-components cancel out, and the resultant electric force on the third charge is along the x-axis (to the right, because it's positive).