Newton's laws of motion: questions and answers
1. A baseball is thrown at `150m//s^2` and its mass is `0.5kg`. What is the force?
`F=mxxa`
`F=0.5kgxx150m//s^2`
`F=75kgm//s^2`
Or
`F=75N` (Newtons)
2. Two skateboarders stand facing each other.
One skateboarder, the woman, weighing `57kg` pushes the other skateboarder the man who is `81kg` with a force of `85N`. What is the acceleration of each skater?
Answer:
Using Newton's third law, the force on the man must be equal and opposite to the womans, so it must be `85`Newtons. We could even say it is minus `85`Newtons.
Now using Newton's second law `F=ma`
Woman
`a=F/m`
`a=(85N)/(57kg)=1.49m//s^2`
Man
`a=F/m`
`a=(-85N)/(81kg)=-1.05m//s^2`
