Answer:
t all= 30h
Explanation:
In this problem the speed of the plane is constant, so we can use the equations of uniform rectilinear motion, the definition of average speed is the distance traveled between the time taken.
v = d / t
Let's calculate each distance
First part of the trip
v₁ = d₁ / t₁
d₁ = v₁ t₁
d₁ = 120 t₁
Second part of the trip
v₂ = d₂ / t₂
d₂ = v₂ t₂
d₂ = 180 t₂
Total trip
v₃ = d₃ / t₃
d₃ = v₃ t₃
d₃ = 170 t₃
The total travel distance is the sum of each distance and the total time is the initial time of 5 h plus the time of the second part (t2)
d₁ + d₂ = 170 t₃
120 5 + 180 t₂ = 170 (5 + t₂)
Let's solve
600 + 180 t₂ = 850 +170 t₂
t₂ (180 -170) = 850 - 600
10 t₂ = 250
t₂ = 25 h
Therefore, the total travel time is
t all= 5 +25 = 30h
Answer is B the frequency changes
It would have 1/6 the potential energy because the gravity is that much less
Answer:
F = 520 N
Explanation:
For this exercise the rotational equilibrium equation should be used
Σ τ = 0
Let's set a reference system with the origin at the back of the refrigerator and the counterclockwise rotation as positive. On the x-axis it is horizontal directed outward, eg the horizontal y-axis directed to the side and the z-axis vertical
Torque is
τ = F x r
the bold indicate vectors, we analyze each force
the applied force is horizontal along the -x axis, the arm (perpendicular distance) is directed in the z axis,
The weight of the body is the vertical direction of the z-axis, so the arm is on the x-axis
-F z + W x = 0
F z = W x
F =
W
The exercise indicates the point of application of the force z = 1.5 m and the weight is placed in the center of mass of the body x = 0.6 m, we are assuming that the force is applied in the wide center of the refrigerator
let's calculate
F = 1300 0.6 / 1.5
F = 520 N