What is Newton’s First Law of Motion? DO NOW! What is Newton’s First Law of Motion?

Review: Newton’s First Law Newton’s first law is also known as… The Law of Inertia.

Review: Newton’s First Law Objects in motion stay in motion, objects at rest, stay at rest.

SWBAT describe Newton’s Second Law and use it to calculate Force. Objective SWBAT describe Newton’s Second Law and use it to calculate Force.

Newton’s second law Newton’s second law says, the amount of acceleration depends on both the force and the mass.

Newton’s second law

Acceleration and force The second law says that acceleration is proportional to force.

If you apply more force to an object, it will accelerate… What does that mean? If you apply more force to an object, it will accelerate… more.

Acceleration and force If you apply less force, the object will accelerate… less.

The stronger the force on an object, the larger its acceleration. twice as much force is applied, the acceleration is twice as large. Because they are directly proportional

Review: Question 1 If you want your soccer ball to really go flying across the field – to accelerate a lot – do you apply a small force (kick it gently) or a large force (kick it hard)? __________________________________

Preview: Question 2 If you push a 2000 kg mass (a car) and a 20 kg mass (a stroller) with the same amount of force, which will accelerate more? _________________

Using units in calculations In terms of solving physics problems, use the following units when using force in Newtons: mass in kilograms (kg) distance or position in meters (m) time in seconds (s) velocity in meters per second (m/s) acceleration in meters per second per second (m/s2)

Objects with greater mass will have less acceleration. Mass is inversely related to acceleration.

The net force causes acceleration. Remember: The net force causes acceleration. If there is no acceleration, net force = 0 N If there is acceleration, there must also be a net force.

Review: Question 3 If something is moving at a constant velocity in the same direction? Is there a net force? No – because that means there is no acceleration. So net force = 0 N.

Practice Questions 4-6 A 1,000 kg car has a 2000 N force exerted on it. What is its acceleration? What is the force on a 1,000 kg elevator that is falling freely under the acceleration of gravity? (g = 9.8 m/s2) What is the mass of an object that requires a force of 50 N to accelerate at 10 m/s2?