Which formula is used to find an object's acceleration?

A 20000 kg subway train initially traveling at 18.5 m/s slows to a stop in a station and then stays there long enough for its br

hodyreva [135]

Answer:

rise the air temperature is 0.179241 K

Explanation:

Given data

mass = 20000 kg

velocity = 18.5 m/s

long = 65 m

wide = 20 m

height = 12 m

density of the air = 1.20 kg/ m³

specific heat = 1020 J/(kg*K)

to find out

how much does the air temperature in the station rise

solution

we know here Energy lost by the train that is calculated by

loss in the kinetic energy that is = 1/2 m v²

loss in the kinetic energy = 0.5 × 20000 ×18.5²

loss in the kinetic energy is 3422500 J

and

this energy is used here to rise the air temperature that is KE / ( specific hat × mass )

so here

air volume = 65 ×20×12

air volume = 15600 m³

air mass = ρ × V = 1.2 × 15600

air mass = 18720 kg

so

rise the air temperature = 3422500 / ( 1020 × 18720)

rise the air temperature is 0.179241 K

7 0

4 years ago

A ball is thrown upward with a speed of 40 m/s. Approximately how much time goes it take the ball to travel from the release loc

yulyashka [42]

Answer:

(I). The time at highest point 4.0 sec.

(II). It returns to back to its original height in 8.1 sec

Explanation:

Given that,

Velocity $v=40\ m/s$

(I). We need to calculate the time at highest point

Using equation of motion

$v=u+gt$

Where, v = final velocity

u = initial velocity

g = acceleration due to gravity

t = time

Put the value into the formula

$0=40-9.8t$

$-40=-9.8t$

$t=\dfrac{40}{9.8}$

$t=4.0\ sec$

(II). We know that, when the ball to travel from the initial point and reached at initial point then the displacement is zero.

We need to calculate the total time when it returns to back to its original height

Using equation of motion

$s=ut-\dfrac{1}{2}gt^2$

Where, s = displacement

g = acceleration due to gravity

t = time

u = velocity

Put the value in the equation

$0=40t-\dfrac{1}{2}9.8t^2$

$80t-9.8t^2=0$

$t=0, 8.1 sec$

Hence. (I). The time at highest point 4.0 sec.

(II). It returns to back to its original height in 8.1 sec

5 0

3 years ago

If a particle's position is given by x=4-12t+3t^2, where t is in seconds and x is in meters, what is its velocity at t=1 second?

andreyandreev [35.5K]

Answer:

v = -6m/s

Explanation:

$x=4-12t+3t^2$

$\frac{dx}{dt}=-12+6t$

For t = 1:

$\frac{dx}{dt}=-6$

3 0

4 years ago

A 150-newton force, applied to a wooden crate at an angle of 30° above the horizontal, causes the crate to travel at constant ve

koban [17]

Answer is in the photo. I can't attach it here, but I uploaded it to a file hosting. link below! Good Luck!

tinyurl.com/wtjfavyw

4 0

3 years ago

This diagram shows a skier moving down a hill. Which statement best describes the skier? The skier has potential and kinetic ene

Troyanec [42]

May you take a picture with the diagram

8 0

3 years ago

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