The force acting in the front direction is the 130N.
The frictional force is acting backwards 30N.
1) The net force is 130N - 30N = 100N
2) s = ut + (1/2)at^2 u = 0, Start from rest, s = 25m t =5.
25 = 0*5 + (1/2)* a * 5^2.
25 = 0 + 25/2 * a.
25 = (25/2)a. Divide 25 from both sides.
1 = (1/2)* a. Cross multiply.
2 = a.
a = 2 m/s^2.
3) Mass of the box
Net Force, F = ma
100 = m*2. Divide both sides by 2.
100/2 = m
50 = m.
m = 50 kg.
4) Final velocity , v = u + at.
v = 0 + 2*5 = 10 m/s.
Kinetic Energy, K = (1/2) * mv^2.
= 1/2 * 50 * 10 * 10.
= 2500 J.
The correct answer is hang glider.
A hang-glider cannot take off from low ground since it has no power. It needs to be launched from a high location, such a mountain or a hill. The major force acting on a hang-glider is gravity. The weight of the wing and the pilot together is this. The push that keeps the aerofoil flying through the air is produced by the weight. The hang-aerofoil glider's wing's form prevents it from falling to the ground like a stone. It results in lift. An area of low pressure is created by the aerofoil's acceleration of the air passing over the top of the wing. The air moving beneath the wing is compressed as the wing moves forward and downward. After then, the aerofoil is lifted up into the region of low pressure.
The air will gradually drop if it is still. A hang-glider descends at a speed of roughly 3.6 km/h (slow walking), or about 1 meter per second. A hang-glider needs to locate air coming up at the same rate as the glider is going down in order to maintain height. A hang-glider can fly along a cliff without losing height, for instance, if there is a light breeze coming straight from the sea, the air is being forced vertically upward by the cliff at 3.6 km/h, and the glider is flying over a vertical coastal cliff. The glider will begin to gain altitude in a stronger breeze.
Some hang-glider pilots equip their craft with tiny motors and propellers. They become microlights as a result and can now take off and climb from flat ground like a regular aircraft.
To learn more about hang-glider refer the link:
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Answer:
Explanation:
When the person stands 5.80 ft from the mirror of the wall.
a) The first image is found by multiplying the distance of the left mirror to the person.
i.e.
2 × 5.80 = 11.6 ft
b) The second image is deduced by the addition of the distance of the first image with the distance created by the right mirror.
i.e.
(2 × 13.7 ) + 11.6
= 39 ft
c) The third image is acquired by the addition of the image presented by the left mirror and the image presented by the right mirror.
(2 × 5.80) + 39
= 50.6 ft
Answer:
n₁ = 3
Explanation:
The energy of the states in the hydrogen atom is explained by the Bohr model, the transitions heal when an electron passes from a state of higher energy to another of lower energy,
ΔE = 
- E₀ = - k²e² / 2m (1 / 
²2 - 1 / n₀²)
The energy of this transition is given by the Planck equation
E = h f = h c / λ
h c / λ = -k²e² / 2m (1 / no ²- 1 / no²)
1 / λ = Ry (1/ ² - 1 / n₀²)
Let's apply these equations to our case
λ = 821 nm = 821 10⁻⁹ m
E = h c / λ
E = 6.63 10⁻³⁴ 3 10⁸/821 10⁻⁹
E = 2.423 10⁻¹⁹ J
Now we can use the Bohr equation
Let's reduce to eV
E = 2,423 10⁻¹⁹ J (1eV / 1.6 10⁻¹⁹) = 1,514 eV
- E₀ = -13.606 (1 / ² - 1 / n₀²) [eV]
Let's look for the energy of some levels
n 
(eV) - E
(eV)
1 -13,606 E₂-E₁ = 10.20
2 -3.4015 E₃-E₂ = 1.89
3 -1.512 E₄- E₃ = 0.662
4 -0.850375
We see the lines of greatest energy for each possible series, the closest to our transition is n₁ = 3 in which a transition from infinity (n = inf) to this level has an energy of 1,512 eV that is very close to the given value
