1. What type of forces are observed in the diagram?

Balanced forces2. Determine the net force placed on the

piano. 25N + 20N = 45N

3. Which way will the piano move?To the right.

1. What type of forces are observed in the diagram?

Unbalanced forces2. Determine the net force placed on the

piano. 12N - 10N = 2N

3. Which way will the piano move?To the right.

1. Describe friction.

Force that acts opposite to the motion of a moving object.

2. What type of surface can increase friction?

Ice

3. What type of surface can increase friction?

Sticky surface

Topic: Forces and Motion

Aim: Describe Newton’s 3 Laws of Motion.

Do Now:

HW:

A student is riding a bike and applies the brakes. What most helps the bike to stop?

1.Friction

2.Heat

3.Gravity

4.Momentum

2 people are pulling at opposite ends of a rope. If they are pulling on the rope with equal but opposite forces, what will happen to the rope?

1.It will stay in place between the 2 people.

2.It will move towards the right.

3.It will move towards the left.

4.It will fall to the ground.

2 people are pulling at opposite ends of a rope. The person pulling on the right side of the rope is applying a force of 50N while the person on the left is applying a force of 70N. What will happen to the rope?

1.It will move towards the right.

2.It will move towards the left.

3.It will fall to the ground.

4.It will stay in place.

When workers spread sand over icy bridges and roads in the winter, how does this help people drive on the roads?

1.The sand increases friction between the road and tires of the car.

2.The sand increases inertia of the car.

3.The sand increases the speed of the car.

4.The sand increases the momentum of the car.

1. Determine the total net force being placed on the rope.

320N – 300N = 20N

1. Which way will the rope be pulled? Support your answer.

The rope will be pulled to the left.

It moves in the direction of the greater force.

The diagram shows the amount of force required to keep the same block of wood moving across the table top.

Explain why the round pencils in diagram 2 decreases the amount of force needed to move the block of wood.

The round pencil decreased the amount of friction.

1. Explain why you feel pulled back when the car is starting and pushed forward when the car stops?

Inertia causes the object to resist a change in motion.

2. Which one of Newton’s laws does this demonstrate?

Newton’s 1st law.

A 60kg water skier is being pulled by a speedboat. The force causes him to accelerate at 2 m/s2. Calculate the force that causes this acceleration.

–F = ma–F = 60kg x 2 m/s2

–F = 120.0 N

A driver steps on the gas and the car gradually accelerates to 50km/h. The driver then slams on the brakes to avoid hitting a box on the road. As the car comes to a stop, the driver’s body appears to lurch forward in the seat until restrained by the seat belt.

Which law best explains why the driver’s body lurches forward when brakes are suddenly applied?

1.Newton’s 1st Law

2.Newton’s 2nd Law

3.Newton’s 3rd Law

4.The law of gravity

The tendency of a stationary object to resist being put into motion is known as

1.acceleration

2.gravity

3.inertia

4.velocity

Which of the following wagons should move faster if pushed with the same force?

1.A wagon containing a boy with a mass of 24kg

2.A wagon containing a small bird with a mass of 10kg

3.A wagon containing a big dog with a mass of 45kg

4.A wagon containing an elephant with a mass of 60kg

1. A chair exerts a force of 20N on the floor. What is the force that the floor exerts on the chair?

1.10N

2.20N

3.21N

4.40N

2. Which one of Newton’s Law is taking place in the question above?

Newton’s 3rd law

1. Describe gravity.

It is the force of attraction between all objects in the universe

2. Explain the relationship between gravity and mass.

As mass increases, gravity increase.

3. Explain the relationship between gravity and distance between 2 objects.

As the distance between 2 objects increases, gravity decreases.

1. Explain the difference between weight and mass.

Weight is the force of measure of the force of gravity on an object.

Mass is the amount of matter in an object.

2. State the acceleration due to gravity on Earth.

ag = 9.8 m/s2

3. State the equation used to determine an object’s weight on earth.

W = mass x ag

1. The moon has a smaller mass than the earth. If you were able to travel to the moon, your weight would

1.increase

2.decrease

3.remain the same

4.vary from day to night

2. What would happen to your mass?

The mass would not change.

The force of gravity on an object depends primarily on the object’s

1.density

2.momentum

3.mass

4.volume

The distance of the star Vega from Earth is 1.6 million times greater than the distance from the sun to the Earth. Which of the following best describes the gravitational influence of Vega on Earth?1.It is roughly equal to that of the sun. 2.Its influence is greater than that of the sun. 3.Its influence is small because of its distance.4.It influences the magnitude of Earth’s mass.

If a solid object is taken from Earth far into space, which of the following measurements of the object will change the most?

1.density

2.mass

3.volume

4.weight

If you were able to go to the top of a building and simultaneously drop an apple and a basketball , they would hit the ground at the same instant because

1.the force of gravity on them is equal

2.they have the same mass

3.air resistance on both is the same

4.they have the same amount of kinetic energy

As a bike rider goes up a hill, the force of gravity acts to

1.increase the weight of the rider

2.increase the acceleration of the rider

3.decrease the weight of the rider

4.decrease the speed of the rider

How would the measureable properties of a golf ball change if it were moved from the earth to the moon?1.It would have the same weight but different mass.2.It would have the same mass but different weight.3.It would have the same density but different mass.4.It would have the same mass but different density.

Which of the following cause a ship’s iron anchor to sink to the ocean floor when released overboard?

1.Nuclear forces

2.Magnetism

3.Gravity

4.Chemical forces

Which of the following statements best describes the force of Earth’s gravity on a rocket moving upwards?1.The gravitational force is constant at all altitudes. 2.The gravitational force is weaker when the rocket is higher. 3.The gravitational force is stronger when the rocket is higher.4.The gravitational force is zero when the altitude is greater than 10, 000 miles.

1.Describe magnetism.

Force of attraction or repulsion.

2. Identify materials attracted to magnets.

Iron, nickel, cobalt, steel

Describe the magnetism occurring in the diagram.

Opposite poles are attracted to each other.

Describe the magnetism occurring in the diagram.

Alike poles repel each other.

1. Describe a magnetic field. An area around magnet where magnetic forces act.

2. Where is magnetic field the strongest?It is strongest at poles

3. What occurs to the magnetic field as the distance from the magnet increases?The magnetic field decreases.

What is the direction of a magnetic field? It moves from north to south.

Describe what is occurring in the diagram.

Poles that are alike repel each other.

S N N