Objectives WARM UP Identify forces of motion Identify Newton’s laws of motion WARM UP Force is the push or pull on an object Forces: gravity, friction, air resistance, etc Hand Out- Day 1: Forces and Motion Worksheet What is force? (In scientific terms) What types of forces make objects move faster, slower, or stop?

Gravity Friction and Gravity Two factors affect the gravitational attraction between objects: mass and distance. Go On

Air Resistance Friction and Gravity Falling objects with a greater surface area experience more air resistance. Go On

Force that opposes motion between two surfaces What is Friction? Force that opposes motion between two surfaces Go On

Discuss with your partner some examples of things we use to decrease friction to help objects move easily. Discuss with your partner some examples of things we use to increase friction to help objects stop moving. Go On

Calculate the net force that causes this acceleration. Finding Force A speedboat pulls a 55-kg water-skier. The force causes the skier to accelerate at 2.0 m/s². Calculate the net force that causes this acceleration. F = mass x acceleration The units of force are newtons (N). The force required to give a 1 kg mass an acceleration of 1 meter per second squared is one Newton 1N = 1kg x 1m/s Go On 2

Finding Force Name: _________________ Class: __________________ Directions: Follow the steps in the example below to complete the problems. EXAMPLE: A speedboat pulls a 55-kg water-skier. The force causes the skier to accelerate at 2.0 m/s2. Calculate the net force that causes this acceleration. What information are you given? Mass of the water-skier (m) = 55 kg and Acceleration of the water-skier (a) = 2.0 m/s2 What quantity are you trying to calculate? The net force (Fnet) = ? What formula contains the given quantities and the unknown quantity? a = Fnet/m or Fnet = m x a Perform the calculation. Fnet = m x a = 55 kg x 2.0 m/s2 F = 110 kg x m/s2 F = 110 N What is the net force on a 1000-kg object accelerating at 3 m/s2? What net force is needed to accelerate a 25-kg cart at 14 m/s2? What will the rate of acceleration be if a 75 N force is applied to a 25-kg crate? BEFORE you go on, be sure your worksheet is complete

Finding Force Name: _________________ Class: __________________ Directions: Follow the steps in the example below to complete the problems. EXAMPLE: A speedboat pulls a 55-kg water-skier. The force causes the skier to accelerate at 2.0 m/s2. Calculate the net force that causes this acceleration. What information are you given? Mass of the water-skier (m) = 55 kg and Acceleration of the water-skier (a) = 2.0 m/s2 What quantity are you trying to calculate? The net force (Fnet) = ? (Measured in Newtons) What formula contains the given quantities and the unknown quantity? a = Fnet/m or Fnet = m x a Perform the calculation. Fnet = m x a = 55 kg x 2.0 m/s2 F = 110 kg x m/s2 F = 110 N What is the net force on a 1000-kg object accelerating at 3 m/s2? What net force is needed to accelerate a 25-kg cart at 14 m/s2? What will the rate of acceleration be if a 75 N force is applied to a 25-kg crate? 2 1000 kg x 3 m/s = 3000 N 25 kg x 14 m/s = 350 N 2 2 25 kg x ? m/s = 75 N ? = 75 N ÷ 25 kg ? = 3 m/s Go On 2

Finding Force Name: _________________ Class: __________________ Directions: Follow the steps in the example below to complete the problems. EXAMPLE: A speedboat pulls a 55-kg water-skier. The force causes the skier to accelerate at 2.0 m/s2. Calculate the net force that causes this acceleration. What information are you given? Mass of the water-skier (m) = 55 kg and Acceleration of the water-skier (a) = 2.0 m/s2 What quantity are you trying to calculate? The net force (Fnet) = ? (Measured in Newtons) What formula contains the given quantities and the unknown quantity? a = Fnet/m or Fnet = m x a Perform the calculation. Fnet = m x a = 55 kg x 2.0 m/s2 F = 110 kg x m/s2 F = 110 N What is the net force on a 1000-kg object accelerating at 3 m/s2? What net force is needed to accelerate a 25-kg cart at 14 m/s2? What will the rate of acceleration be if a 75 N force is applied to a 25-kg crate?

Unbalanced Forces The Nature of Force Unbalanced forces acting on an object result in a net force and cause a change in the object’s motion. Go On 10

Balanced Forces - The Nature of Force Balanced forces acting on an object do not change the object’s motion. Go On 11

BrainPOP Forces http://www.brainpop.com/science/motionsforcesandtime/force/