Answer:
When a particle or a system of particles move in a system where no external force acts, then the total linear momentum of the particle system remains constant.
Explanation:
Given data:
Total mass of the skateboarder, 
Mass of the friend, 
Initial velocity of the skateboarder, 
Initial velocity of the the friend, 
Let the new velocity of the skateboarder when his friend jumps be 
.
From the conservation law of linear momentum,
Answer:
The oldest stars in spiral galaxies are younger than the oldest stars in elliptical galaxies.
Explanation:
Spiral galaxies have a greater star formation than elliptical galaxies, since the latter contain less gas and dust. Therefore, the rate of creation of new stars is lower in elliptical galaxies. These galaxies are dominated by old stars, with a long evolution. While the spiral galaxies have stars with a faster evolution.
The answer is the letter ( d )
The farther the distance, the weaker the gravitational force
Answer:
the mass of a mercury with volume of 263mL = 3559.3 g or 3.56 kg
Explanation:
given:
263 mL liquid mercury
find:
What is the mass of mercury
we know that the density of mercury = 13.5336 g/mL.
now, calculate the mass = volume x density
plugin values into the formula
mass = 263 mL x 13.5336 g/mL.
mass = 3559.3 g or 3.56 kg
therefore,
the mass of a mercury with volume of 263mL = 3559.3 g or 3.56 kg
