What is acceleration What are some examples of

• What is acceleration? • What are some examples of acceleration you observe in your every day experiences? • Today: Newton’s 2 nd Law

Today’s Goal • To begin to explain how force, mass, and acceleration relate to each other.

nd 2 Law F = Force, M = Mass, A = acceleration

nd 2 Law The net force of an object is equal to the product of its mass and acceleration, or F=ma.

What does it mean? F= M x A • What is a force? • A force is a push or a pull. Anything that makes an object move, or stop moving. • What is mass? • Anything that occupies space

What does that mean? • What is an Acceleration? F= M x A

Acceleration • Acceleration = speeding up? ? • Acceleration – the rate at which velocity changes • Can be an: • Increase in speed • Decrease in speed • Change in direction

Types of acceleration • Increasing speed • Example: Car speeds up at green light • Decreasing speed • Example: Car slows down at stop light screeeeech • Changing direction • Example: Car takes turn (can be at constant speed)

Question • How can a car be accelerating if its speed is a constant 65 km/h? • If it is changing directions it is accelerating

Question • There are 3 controls in a car that make it accelerate. What are they? • Accelerator • Brakes • Steering wheel

Back to Newton…. F= M x A Units of Force • When mass is in kilograms and acceleration is in m/s/s, the unit of force is in Newtons (N). • One Newton is equal to the force required to accelerate one kilogram of mass at one meter/second.

nd 2 Law F= M x A How much force is needed to accelerate a 1400 kilogram car 2 meters per second/per second? 1) Write the formula F=mxa 2) Fill in given numbers and units F = 1400 kg x 2 meters per second/second 3) Solve for the unknown 2800 kg-meters/second or 2800 N

Newton’s nd 2 Law • Force, Mass, and Acceleration are all proportional (F, M, A). • Proportional – always behaves in a predicted way • If one factor changes, you know how the others will change. • i. e. When you change the force, you can predict how acceleration will change.

Q: If you change mass, how will it affect A or F? Consider the volleyball and bowling ball (different mass): how will that affect the force you need to achieve the same acceleration? ? =Mx. A A: you will need more force to push the bowling ball

Q: What will happen to the acceleration if you use the same force on the bowling ball and the volley ball? F=Mx? A: the bowling ball will accelerate slower, and the volley ball will accelerate faster.

• Newton’s 2 nd Law is simply an algebraic expression showing how force (F), mass (M), and Acceleration (A) relate to each other: F= M x A http: //www. youtube. com/watch? v=iw. P 4 he. WD hvw&feature=related