Answer:
plane speed: 525mph, jetstream speed=75mph, in explanation it is solved with a linear equations system
Explanation:
First lets name each speed
vs:=speed of the jetstream
vp:=speed of the plane
Now when in the jetstream direction the speeds are added and on the opposite direction are subtracted, then we get these equations, that are linear.
1800 mi=(vp+vs)*3h
1800 mi=(vp-vs)*4h
which is a linear equation system equivalent to:
600 mph=vp+vs (1)
450 mph=vp-vs (2)
Now from (2) vp= 450mph+vs (3), replacing this in (1) we get:
600mph=(450mph+vs)+vs=450mph+2*vs, then 2*vs=150mph or vs=*75mph, this is the jetstream speed, replacing this in (3) we get the plane speed too vp=450 mph +75mph = 525 mph
Answer:
d = 19.92 m
Explanation:
As in this exercise there is friction we must use the relationship between work and energy
W = ΔEm
Look for energy in two points
Initial. Fully compressed spring
Em₀ = 
= ½ k x²
Final. When the block stopped
= 0
Let's look for the work of the rubbing force
W = fr d cos θ
Since rubbing is always contrary to movement, θ = 180
W = - fr d
Let's use Newton's second Law, to find the force of friction
Y Axis
N- w = 0
N = mg
The equation for the force of friction is
fr = μ N
fr = μ mg
We substitute in the work equation
W = - μ m g d
We write the relationship of work and energy
-μ m g d = 0 - ½ k x²
d = ½ k x² / μ m g
Let's calculate
d = ½ 131 2.1 2 / (0.74 2 9.8)
d = 19.92 m
7kinetic energy is decreasing in B
Answer:
a. 4.733 × 10⁻¹⁹ J = 2.954 eV b i. yes ii. 0.054 eV = 8.651 × 10⁻²¹ J
Explanation:
a. Find the energy of the incident photon.
The energy of the incident photon E = hc/λ where h = Planck's constant = 6.626 × 10⁻³⁴ Js, c = speed of light = 3 × 10⁸ m/s and λ = wavelength of light = 420 nm = 420 × 10⁻⁹ m
Substituting the values of the variables into the equation, we have
E = hc/λ
= 6.626 × 10⁻³⁴ Js × 3 × 10⁸ m/s ÷ 420 × 10⁻⁹ m
= 19.878 × 10⁻²⁶ Jm ÷ 420 × 10⁻⁹ m
= 0.04733 × 10⁻¹⁷ J
= 4.733 × 10⁻¹⁹ J
Since 1 eV = 1.602 × 10⁻¹⁹ J,
4.733 × 10⁻¹⁹ J = 4.733 × 10⁻¹⁹ J × 1 eV/1.602 × 10⁻¹⁹ J = 2.954 eV
b. i. Is this energy enough for an electron to leave the atom
Since E = 2.954 eV is greater than the work function Ф = 2.9 eV, an electron would leave the atom. So, the answer is yes.
ii. What is its maximum energy?
The maximum energy E' = E - Ф = 2.954 - 2.9
= 0.054 eV
= 0.054 × 1 eV
= 0.054 × 1.602 × 10⁻¹⁹ J
= 0.08651 × 10⁻¹⁹ J
= 8.651 × 10⁻²¹ J
Answer:
t = 1023.9 seconds
Explanation:
Given that,
The average velocity of a Mustang, v = 33m/s
Distance, d = 21 miles = 33789 m
Let the driver takes t seconds. So,
Speed = distance/time
So, it will take 1023.9 seconds to complete the course.
