PHY 2020 Lecture Notes - Lecture 4: Parachuting, Net Force, Terminal Velocity
Document Summary
Acceleration depends on net force: a= f/m, f= ma. Why does stuff accelerate: an outside force is acting upon it. (1)a 1-kg rock is thrown at 10 m/s straight upward. Three identical blocks are pulled, as show, on a horizontal frictionless surface. Friction: only one fact acts on object- gravity, comes in two (cid:498)flavors(cid:499) static and kinetic (cid:523)sliding(cid:524, static, when stuff at rest and there is friction. Why do we have groves in car tires and none in skateboard tires: tires with grooves to displace and redirect water from between the road surface and underside of the tire. Friction is always opposed to the motion. When sanjay pushed a refrigerator across a kitchen floor at a constant speed the force of friction between the refrigerator and floor is. A 400-kg bear grasping a vertical tree slides down a constant velocity. What is the friction force that acts on the bear: 400 kg * 10 m/s^2 (gravity)= 4,000 n.
