Presentation on theme: "NEWTON’S 2 nd Law of Motion. Newton’s 2 nd law of Motion Describes the relationship of how something with a mass accelerates when it is pushed/pulled."— Presentation transcript:
Units F = m·a = kg·m/s 2 = kg·m/s 2 = Newton = Newton
Example For a while, the National Marbles Tournament was, as one newspaper put it in 1925, "the highest honor possible in the sporting world for (kids).” The game of marbles was a highly competitive game from the early 1900’s to late 1960’s in the United States. The game of marbles was played by propelling a marble with the thumb to hit another marble as to drive it out of a circle. 1950 VFW National Champ Tilton "Pork Chop" Holt in action at the Eaton Rapids, Michigan finals. From LIFE Magazine, June 26, 1950
Example (cont.) “Pork Chop” Holt flicks.036 kg marble at an acceleration of 7.2 m/s 2. What force did he use to propel his marble?
EXAMPLE The Inuit people of the Arctic region, one of the most forbidding territories on Earth, have an economy that revolves around the changing seasons and the animals that could be successfully hunted during these periods. Assume an that an Inuit has caught a sled full of salmon. If he pulls the sled with a force of 80 N and the sled has a mass of 87kg, what is the acceleration of the sled as he pulls it a short distance across the snow?
Example A 15 kg object is being pulled upwards by a force of 3 N and to the left by 4 N. What is the objects acceleration? a = ? m = 15 kg F net = 5 N 4 N 3 N a = F net / m = 5 N / 15 kg = 0.33 m/s 2
Application of Newton’s 2 nd Law: Weight & mass
F w = mg Weight (N) Acceleration caused by gravity (m/s 2 ) Mass (kg)
What’s your mass? Convert pounds into kilograms. What’s your weight in Newtons (on the EARTH)? 9.8 m/s 2 F w = mg
Calculate the following using your information: mass = ____ kg weight = ____ lbs weight = ____ N mass = ____ kg weight = ____ lbs weight = ____ N mass = ____ kg weight = ____ lbs weight = ____ N EarthJupiter Moon g = 9.8 m/s 2 g = 1.6 m/s 2 g = 26 m/s 2
What is the force? If I drag my book across the table with a 3 N force at a CONSTANT VELOCITY, what is the force of friction? Force pulling = 3 N Force of friction = ? a = F net =
What is the force? If I drag my 1.5 kg book across the table with a 3 N force and it accelerates at a rate of 1.1 m/s 2, what is the force of friction? Force pulling = 3 N Force of friction = ? a = 1.1 m/s 2 F net = 1.5 kg