Answer:
Fa = 5000 [N]
Explanation:
To solve this problem we must use Newton's second law, which tells us that the sum of forces on a body is equal to the product of mass by acceleration.
Let's assume that the movement of the plane is to the right, any movement or force to the right will be marked with a positive sign, while any force or movement to the left, will be taken as negative.
The force of the turbine drives the plane to the right, therefore it is positive, the acceleration is constant and keeps the movement to the right, therefore it is positive, the wind drag force tries to prevent the movement of the plane to the left therefore it is negative, with this analysis we deduce the following equation.
ΣF = m*a
where:
ΣF = sum of forces [N] (units of Newtons)
m = mass = 65000 [kg]
a = acceleration = 3 [m/s²]
Fa = force exerted by the air [N]
200000 - Fa = 65000*3
Fa = 200000 - (3*65000)
Fa = 5000 [N]
Answer:
v = 29.4 m / s
Explanation:
For this exercise we can use the conservation of mechanical energy
Lowest starting point.
Em₀ = K = ½ m v²
final point. Higher
= U = m g h
Let's use trigonometry to lock her up
cos 60 = y / L
y = L cos 60
Height is the initial length minus the length at the maximum angle
h = L - L cos 60
h = L (1- cos 60)
energy is conserved
Em₀ = Em_{f}
½ m v² = mgL (1 - cos 60)
v = 2g L (1- cos 60)
let's calculate
v² = 2 9.8 3.0 (1- cos 60)
v = 29.4 m / s
Under the assumption that the three rocks are dropped from the same height, they will hit the ground at the same speed. The gravity of Earth is virtually the same for any object that is small compared to the size of the Earth. The acceleration will change with the distance from the Earth, but this change is so small for the range of heights we work with (consider the range of heights from sea level to the tip of Mount Everest) that we can take the average value and assume it to be constant. This constant value of acceleration due to Earth's gravity is 9.80665m/s²
Because the objects fall under the same constant acceleration, they will hit the ground at the same speed.
