An astronaut in space might feel weightless, but there still is a gravitational attraction between the astronaut and Earth. Which two factors affect this gravitational attraction?

What was the first instrument to ever record an earthquake?

Amoving freight car collides with an identical one that is at rest. if momentum is conserved, what happens to the second car after the collision? it attains the same speed as the first car. it moves at half the speed of the first car. it moves at twice the speed of the first car.

The charge on a charged sphere is; 1. concentrated at its center 2. distributed uniformly throughout its volume 3. clustered on its center 4. distributed uniformly over its surface