With a 30 mph head wind it takes the plane 18.52 hours to fly 5000 miles. ANSWER 2: With a 30 mph tail wind it takes the plane 15.15 hours to fly 5000 miles.
Answer:
fr = 514.5 N, This force has the opposite direction to the applied force.
Explanation:
Let's propose the solution of the problem using Newton's Second Law, we place a reference frame with the horizontal x-axis
Y axis
N- W = 0
N = W
X axis
F -fr = m a
the friction force has the expression
fr = μ N
fr = μ mg
fr = 0.35 150 9.8
fr = 514.5 N
This force has the opposite direction to the applied force.
The student's answer is incorrect because the friction coefficient must be multiplied by the normal
Hello!
We know that at the BOTTOM of the pendulum's trajectory, the bob has a maximum speed. This means that its KINETIC ENERGY is at a maximum, while its Gravitational POTENTIAL ENERGY is at a minimum.
On the other hand, when the bob is at its highest points, the bob has a velocity of 0 m/s, so its KE is at a minimum and its PE is at a maximum.
We can use the work-energy theorem to solve. Let the Initial Energy equal the bob's energy at one of the sides, while the final Energy equals the bob's energy at the bottom.
Recall that:
PE = mgh
m = mass (kg)
g = acceleration due to gravity (m/s²)
h = height (m)
KE = 1/2mv²
m = mass (kg)
v = velocity (m/s)
Set the two equal and solve for 'h'.
Cancel mass.
Solve for 'h'.
Answer:
b) a = 52.26 m / s², a ’= 13.06 m / s², c) N = 2.79 10⁴ N, d) N = 1.89 10³ N
Explanation:
a) In the attached we can see the free body diagrams for the two positions, position A in the lower part of the circle and position B in the upper part of the circle
b) Let's start at point A
Let's use that the acceleration is centripetal
a = v² / r
let's calculate
a = 28² / 15.0
a = 52.26 m / s²
as they relate it is centripetal it is directed towards the center of the circle, therefore for this point it is directed vertically upwards
Point B
a ’= 142/15
a ’= 13.06 m / s²
in this case the acceleration is vertical downwards
c) The values of the normal force
point A
let's use Newton's second law
∑ F = m a
N- W = m a
N = mg + ma
N = m (g + a)
N = 450.0 (9.8 + 52.25)
N = 2.79 10⁴ N
d) Point B
-N -W = m (-a)
N = ma -m g
N = m (a-g)
N = 450.0 (14.0 - 9.8)
N = 1.89 10³ N