Chapter 2 Study Guide Answers Question 1 What two things are needed to describe a vector. Direction and magnitude Remember, force is a vector. Force has a direction (we show it with arrows), and the magnitude is the strength of the force (we measure it in Newtons. The larger the force, the longer the arrow). Question 2 Describe magnitude in two different ways. Size or measurement 10 degrees 50 yards 20 m/s2 25 newtons (Force!) Magnitude is something you can masure. Question 3 Give two examples of units for a force. 200 newtons left 66 newtons south 2 m/s2 south Recall force is a vector and all vectors need direction and magnitude Question 4 Identify all of the Gravity types of forces Normal acting as you sit Applied in your chair. Balanced Question 5 Identify all of the types of forces acting on another object that is moving. Gravity Normal Friction Inertia - maybe If the speed is constant and traveling in a straight line it is balanced. Question 6 What happens where forces are balanced? Net force is zero Motion doesn’t change But it can be moving, just at a constant speed and direction. Recall: velocity changes when an object speeds up, slows down or changes direction. If velocity changes, the forces are UNBALANCED. This is why forces are BALANCED at a constant speed. Question 7 Give two examples of balanced forces. Share out your examples. A car with cruise control on. (Constant speed). An object at rest. Question 8 What happens when forces are unbalanced. Net force is NOT zero Velocity will change therefore acceleration is changing. Slowing down Speeding up Changing direction Question 9 Give two examples of unbalanced forces. Share out your examples. Question 9 Give two examples of unbalanced forces. Share out your examples. One team wins a game of tug-o-war Any object that is changing velocity Question 10 Decrease mass Describe two ways to Increase force increase the magnitude of an For example, how can object’s acceleration. she increase acceleration? Reduce the amount of weights. Increase force by strengthening her muscles Question 11 Put the law of universal gravitation in your words and give an example. All objects are pulled towards each other by gravity. The force of this pull is affected by the size of the two objects and/or the distance between them. Example (pg 97): Earth is large enough and close enough to exert force on us (Gravity pulls from Earth’s core). As Mass increases, Gravity increases (and vice versa) As distance increases, gravity decreses (and vice versa).