Answer:
For cast iron we have

For copper

For Lead

For Zinc

Explanation:
As we know that final speed of the block is calculated by work energy theorem

now we have

now we have


For cast iron we have


For copper


For Lead


For Zinc


Answer:
Less than 1 m
Explanation:
When objects are getting closer to each other there is a slight change in the wavelength that is being transmitted by either objects. This is known as the blue shift of waves. Here, the wavelength reduces.
In the opposite case the when objects are getting farther from each other there is a slight change in the wavelength that is being transmitted by either objects. This is known as the red shift. Here, the wavelength increases.
In this case the spaceship is getting close to Earth hence the wavelength will be lower than 1 m.
Lower. Water expands on lower temperatures, meaning less molecules in 1 m3, thus making it less dense
That's called "refraction".