Activator What does Newton’s first law of motion say? Give an example of this. What is another name for this law?

Newton’s 2nd Law October 16, 2017

Objective SWBAT: calculate how much force is necessary to move an object using Newton’s 2nd Law

Connection On Friday, we learned about Newton’s first law, the law of inertia. Today we are going to talk about Newton’s second law and how to calculate force or acceleration using a formula.

Newton’s Second Law of Motion Newton’s 2nd law says that: Acceleration is produced when a force acts on a mass. The greater the mass, the greater the amount of force needed In other words, the heavier something is, the more force is necessary to move it!

Newton’s Second Law of Motion There is an equation to go with Newton’s 2nd law, and the equation is: Force = Mass x Acceleration  F = M x A In physics, we measure force with units called Newtons (named after Sir Isaac Newton) A newton is the force necessary to accelerate 1 kg of mass at 1 m/s2

Examples of Newton’s Second Law The force required to move a car is much greater than a skateboard. Equal force put into a car and a skateboard would mean that the skateboard would accelerate much faster. If two cars had the same mass, then the one with more force will accelerate faster. NFL Video

Using the Equation Force (Newtons) Equals Mass (kilograms) Times Acceleration (meters per second squared) _________ = 2 kg X 5 m/s2 10 m/s2 20 N 45 N 15 m/s2 40 N 8 kg

Independent Work 1. Determine the accelerations that result when a 12 N net force is applied to a 3 kg object and then to a 6 kg object.

Independent Work 2. A net force of 15 N is exerted on an encyclopedia to cause it to accelerate at a rate of 5 m/s2. Determine the mass of the encyclopedia.

Independent Work 3. Suppose that a sled is accelerating at a rate of 2 m/s2. If the net force (2 N) is tripled and the mass (1 kg) is doubled, then what is the new acceleration of the sled?

Independent Work 4. Suppose that the same sled is accelerating at the same rate of 2 m/s2. If the net force (2 N) is tripled and the mass (1 kg) is cut in half, then what is the new acceleration of the sled?

Exit Ticket You and your bike together have a mass of 60 kg, and you are applying 180 N of force onto the pedals. What is your acceleration?