S4P3

Position is an object’s location or place. * Ex: where you desk is located in the classroom Motion is a change in an object’s position as compared to objects around it. *If you move your desk, its position changes. It’s position changed as compared to the walls.

An object’s location is its (position/motion). The change in an object’s place as compared to objects around it is called (position/motion). How can passengers in a car tell that they are moving?

Speed is a measure of the distance an object travels in a certain amount of time. Speed is measured using units of distance and time. You need to know the distance an object has traveled and how long it took to travel that distance find the speed of an object.

divide distance by time to find speed * ex: A car traveling 100 miles in 2 hours. Divide the distance (100 miles) by the time (2 hours) 100 ÷ 2 = 50 miles per hour (mph)

2-mile race results Runner 115 min 32 s Runner 218 min 50 s Runner 320 min 45 s Look at the chart of race results. Which runner has the slowest speed? Which runner has the fastest speed? How do you know?

The measure of the distance an object travels in a certain amount of time is called: a. position b. motion c. speed d. frame of reference List the two measurements you need to know in order to calculate speed,

Direction tells you which way an object is moving ex: east, west, north, south, right, left, up, down, etc. Velocity is a measure of speed in a certain direction. Speed and direction together determine, or set, velocity.

All the cars are traveling 70m/hr. The cars are constantly changing direction. What else is changing?

Forces are pushes or pulls that cause objects to change their motion. Friction and gravity are to important natural forces. The man pulls on the rake and the leaves move toward him. The boy pushes the wheelbarrow and it moves away from him.

A force can change the motion of an object and a force can stop an object from moving. Which box would take more force to move across the floor? 1 kg 10 kg

When you stop pushing a heavy box, a different force stops the box from sliding. That force is called friction. Friction is a force that slows or stops motion between two surfaces that touch each other. Rough surfaces have more friction than smooth surfaces

Friction between the brake and the wheel on a wheel chair stops the wheel from turning when the brake is used.

Friction keeps things from slipping and sliding. ex: holding a pencil There is even friction between objects and the air. ex: air resistance between air and a bicycle Friction slows or stops movement.

Sometimes, less friction is better. For example, less friction between snow and a snowboard lets the snowboarder go faster.

Add a slippery matter on surfaces that touch Wheels allow objects to roll over a surface

How can a force change the motion of an object? Which objects would produce the least amount of friction when rubbed together? Two sheets of sandpapertwo ice cubessandpaper and an ice cube How does friction stop a bike?

Reducing friction might be useful in which of the following activities? walking ice skatingusing a pencil stopping a bike snowboardingskiing What are some ways to reduce friction?

Gravity is a force that pulls objects towards each other. Gravity pulls skydivers toward the Earth

The force that holds the moon in orbit around the Earth is called a.Frictionb. gravityc. motiond. velocity

Forces are pushes or pulls that cause objects to change their motion. Friction and gravity are two important natural forces. Look at the bowling ball below. What force is acting at each arrow?

Simple machines help people do work by changing a force. A simple machine is a tool that makes work easier by changing a force. A simple machine allows you use less force to move an object.

An inclined plane is a simple machine that is made up of a slanted surface It helps increase the distance over which force is used. It makes work easier

A wedge is a simple machine made up of two inclined planes. Shaped like the letter V. It changes downward force to and outward force. This helps cut or split objects apart.

A screw is a simple machine made up of an inclined plane wrapped around a post. It changes the direction of a force from a turning force to a downward force. The threads of a screw are in inclined plane. The turning force of a screw easily pushes into wood.

A lever is a simple machine made up of a stiff bar that moves freely on a fixed point called a fulcrum. A small force is used on the long end of a lever which creates a large force at the short end.

A wheel and axle is a simple machine made up of two cylinders that turn on the same axis. Using a wheel and axle makes work easier. A water faucet is a wheel and axle. You use a small force to turn the wheel. This creates a large force that turns the axle.

A pulley is a simple machine made up of a rope fitted around the rim of a fixed wheel. Pulleys increase the force or change the direction of the force You pull down on one end of a rope on a pulley to raise a flag or other object.

Describe a pulley. How does the rope and pulley on a flagpole change the direction of the force? Think about a sport or other activity that you enjoy. Describe the forces – pushes, pulls, gravity, and friction – that you use during the activity.