Answer:
The net force on the skater is zero. (
)
Explanation:
According to Newton's First Law, an object is at equilibrium when either it is at rest or moves at constant velocity, which means a net force of zero. Based on the given statement, there are no external forces acting on skate and, therefore, the net force on the skater is zero. (
)
The weight of the meterstick is:

and this weight is applied at the center of mass of the meterstick, so at x=0.50 m, therefore at a distance

from the pivot.
The torque generated by the weight of the meterstick around the pivot is:

To keep the system in equilibrium, the mass of 0.50 kg must generate an equal torque with opposite direction of rotation, so it must be located at a distance d2 somewhere between x=0 and x=0.40 m. The magnitude of the torque should be the same, 0.20 Nm, and so we have:

from which we find the value of d2:

So, the mass should be put at x=-0.04 m from the pivot, therefore at the x=36 cm mark.
We determine the electric potential energy of the proton by multiplying the net electric potential to the charge of the proton. The net electric potential is the difference of the final state to the that of the initial state. So, it would be 275 - 125 = 150 V.
electric potential energy = 150 (<span>1.602 × 10-19) = 2.4x10^-17 J</span>
Answer:
h = 0.46 m
Explanation:
According to the law of conservation of energy:
Potential Energy Lost by Roller Coaster = Kinetic Energy Gained by Roller Coaster

where,
h = height = ?
v = speed at bottom = 3 m/s
g = acceleration due to gravity = 9.81 m/s²
Therefore,

<u>h = 0.46 m</u>