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LekaFEV [45]
3 years ago
12

A train 400 m long is moving on a straight track with a speed of 81.4 km/h. The engineer applies the brakes at a crossing, and l

ater the last car passes the crossing with a speed of 17.6 km/h. Assuming constant acceleration, determine how long the train blocked the crossing. Disregard the width of the crossing.
Physics
1 answer:
Luda [366]3 years ago
3 0

Answer:

86.5m

Explanation:

first convert km/h

then

81.4*1000/60*60=22.6

17.6*1000/60*60=4.89

then, x1/t1=x2/t2

we get

x2=400*4.89/22.6=86.5//

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Weight of 1 kg becomes 1/6 on moon. If radius of moon is 1.76×10^6 m, then the mass of moon will be​
igomit [66]

Answer:

7.65 x 10^22kg

sorry if im wrong!

5 0
2 years ago
Un cuerpo se encuentra en reposo sobre una mesa horizontal. Entonces se puede afirmar que:
vazorg [7]

Answer:

C) solo III

Explanation:

Para solucionar este problema debemos analizar cada una de las opciones hasta llegar a la opcion valida.

I) el cuerpo pesa igual que su masa.

Esta opcion no puede ser ya que el peso de un cuerpo se define como el producto de la masa por la aceleracion gravitacion.

w=m*g

donde:

w = peso [N]

m = masa [kg]

g = aceleracion gravitacional = 9.81 [m/s²]

Como podemos ver el peso siempre sera mayar que la masa, ya que el peso es resultado de la multiplicacion de la masa por la gravedad.

II) Por medio de un analisis de fuerzas en el eje-y, la fuerza del peso se dirige hacia abajo mientras que la fuerza normal tiene igual magnitud, pero se dirige hacia arriba. Por esto la segunda opcion no puede ser.

III) El cuerpo se encuentra en equilibrio, es decir las unicas fuerzas que actuan sobre el cuerpo son el peso y la fuerza normal. Pero estas fuerzas son iguales y opuestas en direccion, por la tanto se cancelan y estan en equilibrio.

Esta es la opcion valida, la fuerza neta es nula.

5 0
3 years ago
What is the relationship between the acceleration of an object change in relation to its mass
yarga [219]

The relationship between mass and acceleration is an inverse proportionality

Explanation:

The relationship between the acceleration of an object and its mass is given by Newton's second law, which states that:

F=ma

where

F is the net force on the object

m is its mass

a is its acceleration

From the equation, we notice that if the force on the object is kept constant, then the mass and the acceleration are inversely proportional to each other. This means that:

  • If the mass of the object is increased, its acceleration will decrease
  • If the mass of the object is decreased, its acceleration will increase

Learn more about Newton's second law:

brainly.com/question/3820012

#LearnwithBrainly

3 0
3 years ago
Suppose a tidal basin is 6 m above the ocean at low tide and that the area of the basin is 5×107 m2. Estimate the gravitational
Neko [114]

Answer:

Potential energy will be 176.58\times 10^{11}j          

Explanation:

We have given the height of the basin is h = 6 m

Area of the basin A=5\times 10^7m^2

Volume V=area \times height=5\times 10^7\times 6=30\times 10^7m^3

Density \rho =1000kg/m^3

We know that mass is given by m=\rho V=1000\times 30\times 10^7=3\times 10^{11}kg

We know that potential energy is given by E=mgh=3\times 10^{11}\times 9.81\times 6=176.58\times 10^{11}j

3 0
3 years ago
How far (in meters) above the earth's surface will the acceleration of gravity be 21.0 % of what it is on the surface?
weeeeeb [17]

Answer:

7532m

Explanation:

Gravity on the surface of the earth with radius R is given by:

F_1=\frac{Gm_{earth}m_{object}}{R^2_{earth}}

Gravity a distance r above the surface:

F_2=\frac{Gm_{earth}m_{object}}{(R+r)^2}

How big is r if:

F_2=0.21\times F_1

You get the following equation:

R^2=0.21(R+r)^2=0.21R^2+0.41Rr+0.21r^2

Solve for r:

r^2+2Rr-\frac{79}{21} R^2=0

r=-R+\sqrt{R^2+\frac{79}{21}R^2}=-R+\sqrt{\frac{100}{21}R^2}=(\frac{10}{\sqrt{21}}-1)R

8 0
3 years ago
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