Describe what a force is and come up with at least 7 important points about forces Objective 1 vocabulary: forceweightNewton Newton spring scale masspoundvectorforce diagram

Objective 1 Definitions: Newtons – the units used to describe forces Mass –a measure of how many atoms are in an object: the more atoms in an object, the higher the mass of the object. Mass is measured in grams (g) or kilograms (kg). Mass is not the same as size. a smaller object can have more mass if the atoms are densely packed together. Weight – a measure of the force of gravity pulling on an object with mass. Since weight is a measurement of the force, weight is measured in Newtons. In the United States weight is measured in pounds (lbs.); when you step onto a scale in the United States, the number of pounds tells you how much the Earth is pulling on you. We will not use pounds in science, only Newtons. Newton spring scale – an instrument used to measure the amount of force. Distances are measured in kilometers or meters, the volume of a liquid is measured in liters or milliliters, and forces are measured in Newtons (N). The higher the number of Newtons, the stronger the force is. Pound – Vector – an arrow that shows the direction and magnitude of a force, the larger the vector – the stronger the force Force diagram - a picture that shows the direction and magnitude of all of the forces acting on an object.

Questions to discuss Identify and draw a force diagram showing all of the forces acting on the box and person: A force is any push or pull motion that always acts in a straight line Forces are measured in Newtons using a Newton Spring Scale. The higher the number of Newtons the stronger the force is. How is it possible for an object to move in a curved path?

Mass is a measure of how much stuff or matter something is made of. Mass does not change with location Weight changes with location because the force of gravity changes.

Mass is measured using a top pan balance or a scale. Mass is measured in kilograms or grams. Weight is measured using a Newton spring scale and is measured in Newtons because weight is a force. Uses*

Mass (g) and weight (N) of an increasing number of weights Number of washers Mass (kg) (divide g by 1000) Weight (force) in Newtons

Questions What was the precision of the spring scale you used? What this an appropriate device to use? Why? Draw a force diagram of the mass on the spring scale. Make a graph of mass (x-axis) versus weight (y-axis) What do the results of your experiment tell you about the relationship between weight (in Newtons) and mass (in kilograms)? At Earth‘s surface the strength of gravity is about 9.8newtons per kilogram. What does this number mean? If an object has a mass of 10kg, how much does it weight in Newtons?

Lab Report discussion: Investigation Questions 1. What makes a good investigation question? 2. If you were to form a lab investigation based on the data you collected here – what possible investigation questions could you ask?