Astronomy | Astrophysics Answers

The following table lists several orbital properties of each planet in the solar system. Mean distances from Sun are expressed in terms of astronomical units (1 AU = 1.496 x 10¹¹ m).

Table: https://cutt.ly/6zq2BQm

You are to obtain some of the values in the table using Newton’s law of universal gravitation. In all calculations involving the mass of Sun, use M = 1.989 × 10³⁰ kg. Assume that all orbits are circular.

1.  Calculate the acceleration of each planet due to the gravity of Sun.

2.  Recall that an object in uniform circular motion experiences acceleration directed towards the midpoint of the circle according to the equation

• a=v²/r

where a is the acceleration of the object, v is the velocity of the object, and r is the radius of the circular path. Calculate the mean orbital velocity of each planet using the above equation. Express your answers in units of km/s.

Sunspots are cooler spots on the Sun’s surface that have a temperature of about 3000-4500 K compared with the average surface temperature of 5800 K. Use this information to explain why calculations involving the inverse square law for the Sun may be inaccurate.

The star Rigel is found 773 light years away in the constellation of Orion. It has a surface temperature of 11000 K and an intensity of 3.7 x 10-8 Wm-2.

i) Calculate the wavelength of the peak in the black body radiation curve of Rigel (2)

ii) Sketch a black body radiation curve for Rigel, ensuring that you label peak wavelength.

iii) Sketch a black body radiation curve for Rigel, ensuring that you label peak wavelength.

If I wanted to study about black hole which book is good

Explain the need to postulate the existence of dark matter in the universe?

A 1 kilogram object is located at a distance of 6.4x10 to the 6th m from the center of a larger object whose mass is 6 by 10 to the 24th kg. Find the gravitational attraction between them.

A research team has discovered that a moon is circling a planet of our solar system: The moonorbits the planet once every 7 hours on a nearly circular orbit in a distance R of 48000 km fromthe centre of the planet. Unfortunately, the mass m of the moon is not known. Use Newton’s lawof gravitation with G = 6.67 · 10−11 m3/(kg·s²) to approach the following questions:F = G ^. mM R2
(a) Based on the observations, determine the total mass M of the planet.(b) Which moon and planet of our solar system is the team observing? (Use literature.)

An astronaut working on the Moon tries to determine the gravitational constant G by throwing a Moon rock of mass m with a velocity of v vertically into the sky. The astronaut knows that the Moon has a density ρ of 3340 kg/m3 and a radius R of 1740 km.(a) Show with (1) that the potential energy of the rock at height h above the surface is given by:
4πG R3
E = −
3 mρ · R + h (2)
(b) Next, show that the gravitational constant can be determined by:
3 v2 .
R Σ−1
(c) What is the resulting G if the rock is thrown with 30 km/h and reaches 21.5 m?

A wire carrying 15 A makes a 25◦angle with a uniform magnetic field. The magnetic force per unit length on the wire is 0.31 N/m. Find:

(a) The magnitude of the magnetic field.

(b) the maximum force per unit length that could be achieved by reorienting the wire.

3) A cyclotron is needed to accelerate protons to (1/30) c( i.e., one-thirtieth the speed of light). The cyclotron magnetic field is 1 T.

(a) What is the minimum radius the cyclotron can have?

(b) What energy would an 'α' particle and a deuteron1have if produced from the same cyclotron?