A solution with a pH of seven must be <br> A. An acid <br> B. A base<br> C.neutral<br> D.water

Answer key says b but i think it is false please help me

klasskru [66]

Energy in a spring:

E = 0.5 * k * x²

k spring constant = 800 n/m
x stretch of the spring = 5 cm = 0.05 m

E = 0.5 * 800 * 0.05² = 1

5 0

3 years ago

I'm pretty sure it's density but I need another opinion.

bixtya [17]

I agree with density

6 0

3 years ago

Read 2 more answers

An astronaut inside a spacecraft, which protects her from harmful radiation, is orbiting a black hole at a distance of 120 km fr

mestny [16]

An astronaut inside a spacecraft, which protects her from harmful radiation, is orbiting a black hole at a distance of 120 km from its center. The black hole is 5.00 times the mass of the sun and has a Schwarzschild radius of 15.0 km. The astronaut is positioned inside the spaceship such that one of her 0.030 kg ears is 6.0 cm farther from the black hole than the center of mass of the spacecraft and the other ear is 6.0 cm closer.

What is the tension between her ears?

Would the astronaut find it difficult to keep from being torn apart by the gravitational forces?

Answer:

The tension between the ears = 2.07 KN

The astronaut will find it difficult to keep and will eventually be in trouble because the tension is now greater compared to the tension in the human tissues.

Explanation:

Given that:

Orbital radius of the spacecraft (R) = 120 Km = 120 × 10³ m

Mass of the black hole (m) = $5 \ * (M \ _{sun})$

where : $M_{sun} = 1.99*10^{33} \ kg$

Then; we have:

$m = 5*(1.99*10^{30} \ kg ) \\ = 9.95*10^{30} kg$

Schwarzchild radius of the black hole

r - 15.0 km

Mass of each ear $m_{ear} = 0.030 \ kg$

Farther distance between one ear and the black hole (d) = 6.0 cm

= 0.06 m

Closer distance between the other ear and the black home is (d) 6.0 cm

= 0.6 cm

NOW, If we assume that the tension force should be T; then definitely the two ears will posses the same angular velocity .

The net force on the ear closer to the black hole will be:

$\frac{GMm_{ear} }{(R-d)}- T = m_{ear} (R - d) \omega^2$

$\frac{GMm_{ear} }{(R-d)^2}- \frac{T}{(R-d)} = m_{ear} \omega^2 \ ----> \ (1)$

The net force on the ear farther to the black hole is :

$\frac{GMm_{ear} }{(R+d)}- T = m_{ear} (R + d) \omega^2$

$\frac{GMm_{ear} }{(R+d)^2}- \frac{T}{(R+d)} = m_{ear} \omega^2 \ ----> \ (2)$

Equating equation (1) and (2) & therefore making (T) the subject of the formula; we have:

$T = \frac{3GMm_{ear}d}{R^3}$

$T = \frac{3(6.67*10^{-11}N.m^2/kg^2)(1.95*10^{30}kg)(0.03kg)(0.06m)}{(120*10^3m)^3}$

$T = 2073.9 N\\T = 2.07 KN$

The tension between the ears = 2.07 KN

The astronaut will find it difficult to keep and will eventually be in trouble because the tension is now greater compared to the tension in the human tissues.

3 0

3 years ago

Why do we use microwaves to communicate berween earth and satellites

nlexa [21]

It’s frequency is high and microwaves can pass through the atmosphere of the Earth.

7 0

3 years ago

Read 2 more answers

Distinguish between contact force and non-contact forces give three examples of each

Artist 52 [7]

Answer:

1. the force which can be felt or act only when two objects are in contact is known as contact force.

for example: frictional force, muscular force,

tension, air resistance .

2. the force which can be felt or act even when two objects are in contact or not is known as non-contact force.

for example: magnetic force, gravitational force, electrostatic force.

6 0

2 years ago

A solution with a pH of seven must be A. An acid B. A base C.neutral D.water