Answer:
The mass of the earth,
Explanation:
It is given that,
Time taken by the moon to orbit the earth,
Distance between moon and the earth,
We need to find the mass of the Earth using Kepler's third law of motion as :
So, the mass of the earth is . Hence, this is the required solution.
Answer:
y = 67.6 feet, y = 114.4/ (22 - 3t)
Explanation:
For this exercise let's use that light travels in a straight line and some trigonometric relationships, the symbols are in the attached diagram
Large triangle Projector up to the screen
tan θ = y / L
For the small triangle. Projector up to the person
tan θ = y₀ / (L-d)
The angle is the same, so we equate the two equations
y₀ / (L -d) = y / L
y = y₀ L / (L-d)
The distance from the screen (d), we look for it with kinematics
v = d / t
d = v t
we replace
y = y₀ L / (L - v t)
y = 5.2 22 / (22 - 3 t)
y = 114.4 (22 - 3t)⁻¹
This is the equation of the shadow height change as a function of time
For the suggested distance the shadow has a height of
y = 114.4 / (22-13)
y = 67.6 feet
Answer:
The total distance is 130.2 [m]
Explanation:
In order to solve this problem we must use the expressions of kinematics. The clue to solve this problem is that the cart starts from rest, i.e. its initial speed is zero.
where:
Vf = final velocity [m/s]
Vo = initial velocity = 0
a = acceleration = 3 [m/s²]
t = time = 8[s]
Vf = 0 + (3*8)
Vf = 24 [m/s]
With this velocity we can calculate the displacement using the following expression.
where
x = distance traveled [m]
24² = 0 + (2*3*x)
x = 576/(6)
x = 96 [m]
Note: The positive sign in the equations is because the car is accelerating, it means its velocity is increasing.
The other important clue to solve this problem in the second part is that the final velocity is now the initial velocity.
We must calculate the final velocity.
Vf = final velocity [m/s]
Vi = initial velocity = 24 [m/s]
a = desacceleration = 1.6 [m/s²]
t = time = 15 [s]
Vf = 24 - (1.6*15)
Vf = 21.6 [m/s]
With this velocity, we can calculate the displacement using the following expression.
where
x = distance traveled [m]
21.6² = 24² - (2*1.6*x)
x = 109.44/(3.2)
x = 34.2 [m]
Note: The negative sign in the equations is because the car is desaccelerating, it means its velocity is decreasing.
Therefore the total distance is Xt = 34.2 + 96 = 130.2 [m].