CH+12+Review

Notes: __Universal Forces__ I. Electromagnetic Forces associated with charged particles ** A. Electric Forces: Forces between charged objects; ex. protons and electron, static cling B. Magnetic Forces: act on certain metals, on poles of magnets and moving charges; ex. magnets with a N or S Pole
 * [|Physical Science Tutorials]
 * **both attract and repel **
 * 

II. Nuclear Forces

A. Strong Nuclear: Acts only on protons and neutrons in the nucleus **
 * **holds them together **
 * **short distances, 100x stronger than electric force **
 * B. Weak Nuclear: occurs in nucleus shorter range**


 * C. Gravitational Force**
 * **weakest force**
 * **attractive force between two masses**
 * **2 Factors; distance and mass**
 * **ex. tides, satellites**
 * 

Review Questions ** Chapter 12 REMEMBER: Final velocity - initial velocity divided by time A 100-kg crate, sliding on a floor, is brought to a stop by 25-N force. What is the deceleration of the crate?
 * Using Formulas **

What is the weight on Earth of a girl with a mass of 30 kg? The acceleration due to gravity on Earth is 9.8 m/s2.

What is the momentum of an 80-kg runner moving at the speed of 2.5 m/s?
 * Calculating **

Which of the following correctly lists friction types (excluding fluid friction) from weakest to strongest? A. sliding, static, magnetic B. static, rolling, sliding C. weak, strong, nuclear D. rolling, sliding, static E. static, sliding, rollin g
 * Standardized Test Prep**

Which statement about an object falling at terminal velocity is TRUE? A. Unbalanced forces act on the object. B. The net force acting on the object is zero. C. The object is accelerating. D. The object is traveling in a circular path. E. No fluid friction acts on the object.

An object changes direction as it moves. Which of the following is FALSE? A. The acting net force is not zero. B. An unbalanced force acts on the object. C. The object is accelerating. D. A centripetal force must act on the object. E. The object's inertia remains unchanged.

Which has the greatest momentum? A. a huge boulder at rest B. a small pebble that is tossed into the air C. a baseball after it is hit with a bat D. a small pebble at rest E. a car traveling on a highway