18.8 mol= mass of He X atomic mass
18.8 mol= mass of He X 4 g mol^-1
mass of He= (18.8 X 4)g = 75.2 g
<span>D deceleration
Hope this helps :)</span>
It's momentum and it's important to understand bc it explains why things do not stop moving after the energy that is being used to make that movement has stopped
