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3 years ago

A 50 kg car is pushed so that it speeds up from 20 m/s to 50 m/s in 3 seconds. What is the force acting on the car?

Physics

1 answer:

egoroff_w [7]3 years ago

3 0

Answer:

A. 500 N

Explanation:

Acceleration is change in velocity over change in time.

a = Δv / Δt

a = (50 m/s − 20 m/s) / 3 s

a = 10 m/s²

Force is mass times acceleration.

F = ma

F = (50 kg) (10 m/s²)

F = 500 N

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Erosion, weathering, mechanical changes, chemical changes.

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3 years ago

Read 2 more answers

Problem One: A beam of red light (656 nm) enters from air into the side of a glass and then into water. wavelength, c. and speed

Ivanshal [37]

Answer:

Part a)

$f_w = f_g = 4.57 \times 10^{14} Hz$

Part b)

$\lambda_w = 492 nm$

$\lambda_g = 437.3 nm$

Part c)

$v_w = 2.25 \times 10^8 m/s$

$v_g = 2.0 \times 10^8 m/s$

Explanation:

Part a)

frequency of light will not change with change in medium but it will depend on the source only

so here frequency of light will remain same in both water and glass and it will be same as that in air

$f = \frac{v}{\lambda}$

$f = \frac{3 \times 10^8}{656 \times 10^{-9}}$

$f = 4.57 \times 10^{14} Hz$

Part b)

As we know that the refractive index of water is given as

$\mu_w = 4/3$

so the wavelength in the water medium is given as

$\lambda_w = \frac{\lambda}{\mu_w}$

$\lambda_w = \frac{656 nm}{4/3}$

$\lambda_w = 492 nm$

Similarly the refractive index of glass is given as

$\mu_w = 3/2$

so the wavelength in the glass medium is given as

$\lambda_g = \frac{\lambda}{\mu_g}$

$\lambda_g = \frac{656 nm}{3/2}$

$\lambda_g = 437.3 nm$

Part c)

Speed of the wave in water is given as

$v_w = \frac{c}{\mu_w}$

$v_w = \frac{3 \times 10^8}{4/3}$

$v_w = 2.25 \times 10^8 m/s$

Speed of the wave in glass is given as

$v_g = \frac{c}{\mu_g}$

$v_g = \frac{3 \times 10^8}{3/2}$

$v_g = 2 \times 10^8 m/s$

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3 years ago

A man has been guarding a house for one hour . Why is it not considered work in science

leva [86]

Answer: because there is no displacement or movement in the watchman's work. according to science when displacement or movement take place it is said to be work. hope this helps you.

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3 years ago

How long will the ball be in the air if the cliff is 120 m tall and the ball falls to the base of the cliff?

Readme [11.4K]

Answer:

Explanation:

4.95s≈5s

Use equation :

h=G*t²/2

h=120m ----hight of cliff

G=9.81m/s²

t=?

-----------------------

h=G*t²/2

120m=9.81m/s²*t²/2

240m=9.81m/s²*t²

t²=240m/ 9.81m/s²

t²=24.46s

t=√24.46s²

t=4.95 s≈5s

3 0

3 years ago

Un objeto que es empujado sobre una superficie plana, tiene una masa de 80 kg y dicha fuerza tiene un valor de 300 N. Calcule la

Gennadij [26K]

Responder:

A. Ff = 300 N N = 784,8 N

Explicación:

Dado

Masa del cuerpo = 80 kg

Fuerza de movimiento Fm = 300N

Dado que el cuerpo no está acelerando, la fuerza de fricción (Ff) es igual a la fuerza de movimiento que actúa sobre el cuerpo, ya que la fuerza de fricción es una fuerza de oposición, es decir, Fm = Ff

Dado que Fm = 300N, Ff = 300N

La reacción normal que actúa en el cuerpo es igual al peso.

N = W = mg

g es la aceleración debida a la gravedad

g = 9,8 m / s

N = mg

N = 80 (9,81)

N = 784,8N

Por tanto, la fuerza normal que actúa sobre el cuerpo es 784,8 N

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2 years ago