Forces NL 3.1
Force is a push or pull in a particular direction – Forces have different magnitudes and directions Motion is an object’s change in position over time. Forces cause a change in motion REFRESHER
What are examples of forces that we see on earth every day?
Friction is the force that holds back the movement of a sliding object. It acts in the opposite direction of the way an object wants to slide.
Gravity or gravitational forces are forces of attraction. Earth pulls on you to keep you on the ground Every object that has mass exerts a gravitational pull on every other mass – The size of the pull depends on the masses of the objects – This is what holds moons to their planets and the planets to our Sun.
Gravity is what causes an object to fall to the ground. In a vacuum (where there is no air) a feather will fall at the same speed as a dense ball
Momentum is an indication of how hard it would be to stop an object. – When the mass is greater (at the same speeds) the momentum is greater. – Think about the ping pong ball and golf ball. They had the same volume, and relatively the same speed. Which one was harder to stop?
Just like in Newton’s 1 st Law, momentum will remain the same unless acted upon by an outside force – When that happens we say that momentum is conserved – This is why the golf ball moved the block. The greater mass had a greater momentum which could only be stopped when it hit that wooden block.