If a neutron star has a radius of 15 km and rotates 748 times a second, what is the speed of the surface at the neutron star's equator as a fraction of the speed of light?

The mass of an electron is 9.11 x 10 ^-31 kg. The mass of a proton is 1.67 x 10 ^-27 kg. They are about 5.3×10^ −11 m apart in a hydrogen atom. What is the gravitational force between these two particles in the hydrogenatom?

The Oort Cloud extends out to (possibly) one light-year from the sun.  Objects in the Oort Cloud are still gravitationally bound to the sun.  Suppose one such iceball orbits the sun in a circle.  I'm going to alter some numbers, such as the mass of the sun and even G.  The gravitational force is directed toward the sun and has the following magnitude: Calculate the force on the object if these are the numbers: G = 6.1*10-11 N*m2/kg2 M = 2.7*1030 kg m = 1.5*108 kg r = 19*1015 m Calculate your answer in microNewtons (10-6 N).

A space probe of mass 3.9 x 103 kg is orbiting a star of mass 3.6 x 1030 kg  in a circular orbit at a distance of 1.7 x 1011 m from its center.  Calculate the minimum energy, in units of 109 J, required to transfer the probe to a circular orbit 5.5 x 1011 m from the star.  Use G = 6.7 x 10-11 N m2/ kg2. (Please answer to the fourth decimal place - i.e 14.3225)

When a falling meteoroid is at a distance above the Earth's surface of 2.4 times the Earth's radius, what is its acceleration due to the Earth's gravitation? (Units: m/s2)

A spaceship is moving in an elliptical motion. Their position (x, y) is described by the equation (x^2)/4 + (y-5)^2 = 9 Here, x represents their horizontal position (in km) and y represents the height (in km) of the spaceship: (a) An observer at a certain instant sees the shadow of the spaceship at x = 2 km and observes that the shadow is moving with a speed of 100 km per hour in the positive x direction. The observer also notes that the spaceship is ascending at this instant. How fast is the vertical motion of the spaceship at this instant? Give an exact answer. (b) Assuming that the spaceship doesn’t alter its course, is it moving in a clockewise or counterclockwise motion? (c) The speed of the spaceship is defined by the quantity Square root ((dx/dt)^2 + (dy/dt)^2). What is the speed of the spaceship in Part (a)? You may approximate

I need help with this hw problem.

I'm having trouble completing the problem I've attached a picture of below. I was able to find the the Earth's average speed in m/s relative to the sun by doing (2pi*(1.49x10^11))/31536000. But I am struggling to find the average velocity for the same thing over a period of one year in m/s. I was wondering how to calculate that? I've tried doing the (final velocity-initial velocity)/2 but the program doesn't accept my answer when using that approach.

I was not able to solve this physics problem, please help me solve it and circle your answer. Thank you.

Suppose astronomers found evidence of an earth-like planet 20 lightyears away. a) what may be two ethical considerations that one may consider when deciding if humans should travel to this planet? b) how fast would a spaceship need to travel if the roundtrip can no take longer than 40 years for the astronauts? c) how much time will the trip take according to the people on earth?