science test - Newton’s law of motion, friction, gravity, forces

contact force

push or pull on 1 object by another object that is touching it

ex: friction

noncontact force

push or pull on 1 object by another object that is not touching it

ex: gravity → electrical and magnetic

net force

the combination of all the forces acting on an object

balanced forces

forces acting on an object that combines a net force of zero. No change in motion.

unbalanced forces

forces acting on an object that combine and form a net force that is not zero → motion of objects

Newton’s first law

aka law of inertia

in the absence of a net force a body at rest will remain at rest and a body in motion will remain in motion indefinitely along the same straight line

ex: ball rolling down a hill, kicking a soccer ball, playing tug of war, spinning a marble around a cup and releasing

Newton’s second law

aka law of acceleration

in the presence of a net force, an object experiences an acceleration

ex: car accelerating

Newton’s second law formula

force = mass x acceleration

Newton’s third law

aka law of action and reaction

for every action, there is an equal and opposite reaction

ex: rocket

inertia

the tendency of an object to resist a change in motion. 

friction

the rubbing force that acts against motion between two touching surfaces 

what two factors affect gravity?

mass and distance

gravity

the attractive force between two objects that depend on their mass and distance between them → as distance decreases, gravity increases

mass

how much matter an object has

weight

gravitational force exerted on an object → depends on the mass and strength of gravitational pull

momentum

a measure of how hard it is to stop a moving object