a) 0.321 ly
b) 0.321 light years is not far in astronomical terms. Alien life would need to transmit at tremendous power in order for their radio transmissions to be detectable. Their radio signal also needs to be stronger than background noise in order to be distinguishable. Therefore it is unlikely that radio transmissions from alien life will ever be detected.
A convex mirror makes a reflected light rays spread out.
Your question kind of petered out there towards the end and you didn't specify
the terms, so I'll pick my own.
The "Hubble Constant" hasn't yet been pinned down precisely, so let's pick a
round number that's in the neighborhood of the last 20 years of measurements:
<em>70 km per second per megaparsec</em>.
We'll also need to know that 1 parsec = about 3.262 light years.
So the speed of your receding galaxy is
(Distance in LY) x (1 megaparsec / 3,262,000 LY) x (70 km/sec-mpsc) =
(150 million) x (1 / 3,262,000) x (70 km/sec) =
<em>3,219 km/sec </em>in the direction away from us (rounded)
When Debbie pushes the first cart she is using an applied force. An applied force is created when someone or something pushes another thing using, of course, an applied force. Now, when the second cart is being pushed by the first cart, this is also an applied force. You can tell because the first cart is being pushed using forced and this causes the second cart to be pushed using some of the force that is being transmitted to the first cart.
Debbie exerts applied force on the first cart. The first cart exert applied force on the second cart.
- Marlon Nunez