Answer:
Explanation:
The center of mass of the system (two girls) is constant, as the velocity of the center of mass of the system is also constant.
<u>The initial velocity of the system is zero, since both girls are at rest.</u> So the velocity of the total system at any point should be zero as well.
This is true, because there is no friction between the girls and the ground. Otherwise, the velocity of the center of mass wouldn't be constant.
A. Jenna because an optimistic person always has a healthier look in life!
Answer:
gravitational force increases
Explanation:
Since gravitational force is inversely proportional to the square of the separation distance between the two interacting objects, more separation distance will result in weaker gravitational forces. So as two objects are brought closer to each other, the force of gravitational attraction between them also increases.
Answer:
τ = (7.96 x 10⁴ m⁻³)T
This is the expression for maximum allowable shear stress in terms of the maximum torque applied in Nm.
Explanation:
The maximum allowable shear stress on the solid shaft can be given by the torsional formula as follows:
τ = Tc/J
where,
τ = Maximum Allowable Shear Stress = ?
T = Maximum Torque Applied to the Shaft
c = maximum distance from center to edge = radius in this case = 20 mm = 0.02 m
J = Polar Moment of inertia = πr⁴/2 = π(0.02 m)⁴/2 = 2.51 x 10⁻⁷ m⁴
Therefore,
τ = T(0.02 m)/(2.51 x 10⁻⁷ m⁴)
<u>τ = (7.96 x 10⁴ m⁻³)T</u>
<u>This is the expression for maximum allowable shear stress in terms of the maximum torque applied in Nm.</u>
Answer:
The angle's rate of change is: -0.125 (degree/feet).
Explanation:
In this case of problem we need to find the angle's rate (α) of change when x=6 ft. First we need to relate (α) with x and y and the expression that do it is: 
where (α) is the angle between the ladder and the ground, x is the horizontal distance and y the vertical distance, now we need to have the variable y at function of x, so we can do it using the Pythagorean theorem and gets:
solving for y(x) we get:
. Replacing all we have got in the first equation: 
. Finally we derivate this equation at function of variable x and gets this result:
evaluating at x=6 ft we get: -0.125(degree/feet). The negative signal means that the angle is decreasing.
