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If a single constant force acts on an object that moves on a straight line, the object's velocity is a linear function of time.

olya-2409 [2.1K]

Answer:

$F=mkv$

Explanation:

Given that

$v = v_i - kx$

We know that acceleration a given as

$a=\dfrac{dv}{dt}$

$v = v_i - kx$

$\dfrac{dv}{dt}=\dfrac{dv_i}{dt}-k\dfrac{dx}{dt}$

$\dfrac{dv}{dt}=0-k\dfrac{dx}{dt}$

We know that

$F=m\dfrac{dv}{dt}$

$F=-mk\dfrac{dx}{dt}$

$F=-mkv$

So the magnitude of force F

$F=mkv$

5 0

3 years ago

If the box is a distance 1.81 m from the rear of the truck when the truck starts, how much time elapses before the box falls off

alexira [117]

If the box is a distance 1.81 m from the rear of the truck when the truck starts, ... Force of Friction = mu_s * Normal Force( M * G) ... The box starts moving! ... Now that the box is moving, the bed of the truck pulls at it with 17.4 ... out how long it will take the box to reach the back of the truck. ... T^2 = 2 * 1.81 / .64

4 0

3 years ago

A film of soapy water on top of a plastic cutting board has a thickness of 255 nm. What wavelength and color is most strongly re

Alona [7]

Answer:

the reflected wavelength is lano = 4.55 10⁻⁷ m which corresponds to the blue color

Explanation:

This is a case of reflection interference, we must be careful

* There is a 180º phase change when light passes from the air to the soap film (n = 1,339), but there is no phase change when passing from the pomp to the plastic (n = 1.3)

* the wavelength within the film is modulated by the refractive index

λₙ = λ₀ / n

if we consider these relationships the condition for constructive interference is

2 t = (m + ½) λₙ

2t = (m + ½) λ₀ / n

λ₀ = 2t n / (m + ½)

we substitute the values

λ₀= 2 255 10⁻⁹ 1,339 / (m + ½)

λ₀ = 6.829 10⁻⁷ (m + ½)

let's calculate the wavelength for various interference orders

m = 0

λ₀ = 6.829 10⁻⁷/ ( 0 + ½ )

λ₀ = 13.6 10⁻⁷

it is not visible

m = 1

λ₀ = 6,829 10⁻⁷/ (1 + ½)

λ₀ = 4.55 10⁻⁷

color blue

m = 2

λ₀ = 6.829 10⁻⁷ / (2 + ½)

λ₀ = 2,7 10⁻⁷

it is not visible

therefore the reflected wavelength is lano = 4.55 10⁻⁷ m which corresponds to the blue color

5 0

3 years ago

(i) Calculate the energy, in electron volts, of a photon whose frequency is (a) 620 THz}, (b) 3.10GHz , and(c) 46.0 MHz

DedPeter [7]

The energy in electron volts of the photons that has the following frequencies is as follows:

620 THz = 2.564eV
3.10GHz = 1.28 × 10-⁵eV
46.0 MHz = 1.902 × 10-⁷eV

<h3>How to calculate energy?</h3>

The energy of a photon can be calculated using the following formula:

E = hf

Where;

E = energy
h = Planck's constant (6.626 × 10-³⁴ J/s)
f = frequency

First, we convert the frequencies to hertz as follows;

620THz = 6.2 × 10¹⁴Hz
3.10GHz = 3.1 × 10⁹Hz
46.0MHz = 4.6 × 10⁷Hz

E = 6.626 × 10-³⁴ × 6.2 × 10¹⁴ = 2.564eV
E = 6.626 × 10-³⁴ × 3.1 × 10⁹ = 1.28 × 10-⁵eV
E = 6.626 × 10-³⁴ × 4.6 × 10⁷ = 1.902 × 10-⁷eV

Learn more about energy of a photon at: brainly.com/question/2393994

#SPJ1

6 0

1 year ago

Jumping up before the elevator hits. After the cable snaps and the safety system fails, an elevator cab free-falls from a height

noname [10]

Answer:

a) I = 2279.5 N s , b) F = 3.80 10⁵ N, c) I = 3125.5 N s and d) F = 5.21 10⁵ N

Explanation:

The impulse is equal to the variation in the amount of movement.

I =∫ F dt = Δp

I = m $v_{f}$ - m v₀

Let's calculate the final speed using kinematics, as the cable breaks the initial speed is zero

$v_{f}$ ² = V₀² - 2g y

$v_{f}$ ² = 0 - 2 9.8 30.0

$v_{f}$ = √588

$v_{f}$ = 24.25 m/s

a) We calculate the impulse

I = 94 24.25 - 0

I = 2279.5 N s

b) Let's join the other expression of the impulse to calculate the average force

I = F t

F = I / t

F = 2279.5 / 6 10⁻³

F = 3.80 10⁵ N

just before the crash the passenger jumps up with v = 8 m / s, let's take the moments of interest just when the elevator arrives with a speed of 24.25m/s down and as an end point the jump up to vf = 8 m / n

c) I = m $v_{f}$ - m v₀

I = 94 8 - 94 (-24.25)

I = 3125.5 N s

d) F = I / t

F = 3125.5 / 6 10⁻³

F = 5.21 10⁵ N

7 0

3 years ago