牛顿第一定律英文.pptx

Newtons First Law of Newtons First Law of MotionMotion Law of Inertia Miha LeeNewtons First Law of MotionNewtons First Law of MotionEvery object in a state of uniform motion tends to remain in that state of motion unless an unbalanced force is applied to it.An object at rest An object in motionAn Object at RestAn Object at RestAn Object in MotionGalileos thought experiment I An Object in MotionGalileos thought experiment IIFrictional forceFrictional forceFrictionFriction is the force that acts on a moving object to slow it down and bring it to stop.Question 1:Evaluate the following assertion.If there is no frictional force on the road,cars can move without consumption of energy by the Newtons first law of motion.So we can save energy.An Object in MotionAn Object in MotionA dynamic cart with a brick on it.Get it moving and stopped.Tape the brick to the cart.Get it moving and stopped again.Seat belts protect us from being hurt by keeping us tied to the vehicle.An Object in MotionInertiaInertiaThe resistance an object has to a change in its state of motion.Question 2:What does the magnitude of inertial force depend on?F=ma m:inertial massApplication to everyday lifeOpening a bottleRemoving dusts from clothsSeat beltsSeismometerSeat BeltSeat belts can exert forces to cause passengers to slow down at the same rate as the vehicle.Question 3:How does a seat belt exert force on us?The principle of retractorsThe principle of retractors