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1 year ago

A friend frequently misses the morning

Physics

1 answer:

poizon [28]1 year ago

7 0

Answer: Heyaa! ~

State of the problem is that your friend routinely misses the school bus.

Explanation:

What are the causes for his missing the school bus:

Not waking early enough

Too long breakfast

Too far to the bus stop.

Deliberately tries to miss the bus.

Hopefully this helps you!

-Matthew ^^

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Franny drew a diagram to compare images produced by concave and convex lenses.

yanalaym [24]

Answer:

virtual

Explanation:

4 0

2 years ago

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A quantity of a gas has an absolute pressure of 400 kPa and an absolute temperature of 110 degrees kelvin. When the temperature

shepuryov [24]

You can make sure there's no change in volume by keeping
your gas in a sealed jar with no leaks. Then you can play with
the temperature and the pressure all you want, and you'll know
that the volume is constant.

For 'ideal' gases,

   (pressure) times (volume) is proportional to (temperature).

And if volume is constant, then

   (pressure) is proportional to (temperature) .

So if you increase the temperature from 110K to 235K,
the pressure increases to (235/110) of where it started.

   (400 kPa) x (235/110) = 854.55 kPa. (rounded)

Obviously, choice-b is the right one, but
I don't know where the .46 came from.

4 0

3 years ago

You may have noticed runaway truck lanes while driving in the mountains. These gravel-filled lanes are designed to stop trucks t

Sladkaya [172]

Answer:

0.767

Explanation:

The work done on the truck by the frictional drag force is given by

$W=-Fd$

where

F is the magnitude of the frictional force

d = 38.0 m is the maximum displacement allowed for the truck

The negative sign is due to the fact that the force of friction is opposite to the motion of the truck

The force of friction can also be written as:

$F=\mu mg$

where

$\mu$ is the coefficient of kinetic friction between the truck and the lane

m is the mass of the truck

g is the acceleration of gravity

So we can rewrite the work done as

$W=-\mu mg d$ (1)

According to the work-energy theorem, the work done by friction is equal to the change in kinetic energy of the truck:

$W=K_f - K_i = \frac{1}{2}mv^2-\frac{1}{2}mu^2$ (2)

where

v = 0 is the final velocity of the truck

u = 23.9 m/s is the initial velocity of the truck

By combining (1) and (2) we get

$-\frac{1}{2}mu^2 = -\mu mg d$

And solving for $\mu$ , we find the minimum coefficient of kinetic friction able to stop the truck in a distance d:

$\mu = \frac{u^2}{2gd}=\frac{23.9^2}{2(9.8)(38.0)}=0.767$

7 0

3 years ago

How does electricity flow?

DedPeter [7]

Current flows from High Potential (Positive) to Low potential (Negative)

So, option D is your answer!

Hope this helps!

3 0

3 years ago

Read 2 more answers

A vertical spring withk= 245N/m oscillates with an amplitude of 19.2cm when 0.457kg hangs from it. The mass posses through the e

Makovka662 [10]

Answer:

y = -19.2 sin (23.15t) cm

Explanation:

The spring mass system is an oscillatory movement that is described by the equation

y = yo cos (wt + φ)

Let's look for the terms of this equation the amplitude I

y₀ = 19.2 cm

Angular velocity is

w = √ (k / m)

w = √ (245 / 0.457

w = 23.15 rad / s

The φ phase is determined for the initial condition t = 0 s , the velocity is negative v (0) = -vo

The speed of the equation is obtained by the derivative with respect to time

v = dy / dt

v = - y₀ w sin (wt + φ)

For t = 0

-vo = -yo w sin φ

The angular and linear velocity are related v = w r

v₀ = w r₀

v₀ = v₀ sinφ

sinφ = 1

φ = sin⁻¹ 1

φ = π / 4 rad

Let's build the equation

y = 19.2 cos (23.15 t + π/ 4)

Let's use the trigonometric ratio π/ 4 = 90º

Cos (a +90) = cos a cos90 - sin a sin sin 90 = 0 - sin a

y = -19.2 sin (23.15t) cm

8 0

3 years ago