Ask question

Ask question

All categories

2 years ago

15

What question did use of a telescope by hubble answer A) Is earth the center of the universe B) Is the sun the center of the uni

verse C) How do the planets move in the solar system D) Are there more galaxies beyond the milky way

2 answers:

Marta_Voda [28]2 years ago

6 0

Answer:c

Explanation:

cestrela7 [59]2 years ago

3 0

Answer: C

Explanation:

You might be interested in

A simple model of the hydrogen atom suggests that the electron orbits the proton. What is the

andrey2020 [161]

If I remember correctly, the correct answer is either:
A. Electrostatic
or
B. Gravitational

7 0

3 years ago

Six dogs pull a two-person sled with a total mass of 220 kg. The coefficient of kinetic friction between the sled and the snow i

irina [24]

Answer:

a) 2457J

b) 558W

c) 337N

Explanation:

Assuming dogs started from rest.

$v=a*t\\t=\frac{a}{v}\\v=12\frac{km}{h}\frac{1000m}{km}*\frac{1h}{3600s}\\\\v=3.3m/s\\\\t=\frac{3.3m/s}{0.75m/s^2}\\t=4.4s$

and the displacement is given by:

$d=\frac{1}{2}*a*t^2\\d=7.3m$

Using the energy conservation formula:

$K_i+U_i+W_d+W_f=K_f+U_f$

Because the motion started from rest the initial kinetic energy is zero, the motion occurred in-ground level so the gravitational energy is zero too.

the work done by the friction force is given by:

$W_f=F_f*d*cos(\theta)\\W_f=\µ*m*g*d*cos(180)\\W_f=0.08*220kg*9.8m/s^2*7.3m*(-1)\\W_f=-1259J$

so:

$W_d=\frac{1}{2}*220kg*(3.3m/s)^2+1259J\\W_d=2457J$

The power is given by:

$P=\frac{W}{t}\\\\P=\frac{2457J}{4.4s}\\\\P=558W$

and the force exerted by the dogs:

$W_d=F_d*d*cos(\theta)\\F_d=\frac{W_d}{d*cos(0)}\\\\F=\frac{2457J}{7.3m*(1)}\\\\F=337N$

4 0

2 years ago

A wooden ring whose mean diameter is 15.0 cm is wound with a closely spaced toroidal winding of 555 turns. Compute the magnitude

ruslelena [56]

Answer:

9.916\times 10^{-4}T

Explanation:

Diameter of toroid is 15 cm =0.15 m

So length of the toroid is $l=\pi d=3.14\times 0.15=0.471\ m$

Number of turns of the toriod is given as 555

Current through the toroid is 0.670 A

Magnetic field $B=\mu _0ni=\mu _0\frac{N}{L}i=4\pi \times 10^{-7}\times \frac{555}{0.471}\times 0.670=9.916\times 10^{-4}T$

7 0

3 years ago

Which process requires more energy: completely vaporizing 1 kg of saturated liquid water at 1 atm pressure or completely vaporiz

Lilit [14]

The correct answer would be the first option. The process that would need more energy would be vaporizing 1 kg of saturated liquid water at a pressure of 1 atmosphere. This can be seen from the latent heat of vaporization of each system. For the saturated water at 1 atm, the latent heat is equal to 40.7 kJ per mole while, at 8 atm, the latent heat is equal to 36.4 kJ per mole. The latent heat of vaporization is the amount of heat needed in order to vaporize a specific amount of substance without any change in the temperature. As we can observe, more energy is needed by the liquid water at 1 atm.

7 0

3 years ago

You are 12 miles north of your base camp when you begin walking north at a speed of 2 miles per hour. What is your location, rel

liubo4ka [24]

If you walk at a pace of 2 miles per hour for 5 hours, you should have walked 10 miles. You would be 2 miles away from your base camp.

8 0

3 years ago

Read 2 more answers