Physical Science Chapter 12 Practice Test Name



Physical Science Chapter 12 Practice Test Name_____________________

Modified True/False

Indicate whether the sentence or statement is true or false. If false, change the identified word or phrase to make the sentence or statement true.

____ 1. If a person tries to lift a heavy box for 5 seconds and can’t make it budge, the work done on the box is less than zero. _________________________

____ 2. Machines decrease the amount of energy that is needed to do work. _________________________

____ 3. Because of friction, using machines increases the amount of energy that is needed to do work _________________________

____ 4. An arrangement of multiple pulleys causes the direction of the output force to be opposite to the direction of the input force. _________________________

Multiple Choice

Identify the letter of the choice that best completes the statement or answers the question.

____ 5. What are the units of work?

|a. |J |c. |kg•m2/s2 |

|b. |N•m |d. |All of the above |

____ 6. Which of the following processes requires the most work?

|a. |A 10 kg weight rests on a table. |

|b. |A person holds a 1 kg weight still with outstretched arms. |

|c. |A person lifts a 1 kg weight 1 m off the floor. |

|d. |A 10 kg ball is rolled across the floor at a constant speed for a distance of 10 m. |

____ 7. What are the units of power?

|a. |watts |c. |joules per second |

|b. |horsepower |d. |All of the above |

____ 8. A machine is a device that

|a. |requires less work to do a given task. |

|b. |decreases the amount of work done by a given force. |

|c. |increases energy. |

|d. |can multiply and change the direction of an input force. |

____ 9. A first-class lever has the

|a. |fulcrum at one end and the output force between the fulcrum and the input force. |

|b. |fulcrum at one end and the input force between the fulcrum and the output force. |

|c. |fulcrum in the middle. |

|d. |input force in the middle. |

____ 10. A wheelbarrow is an example of a

|a. |first-class lever. |c. |third-class lever. |

|b. |second-class lever. |d. |fourth-class lever. |

____ 11. Which of the following is an example of a wheel and axle?

|a. |a block and tackle |c. |a screwdriver |

|b. |a pulley |d. |a nutcracker |

____ 12. Which of the following is not in the inclined plane family?

|a. |a wedge |c. |a ramp |

|b. |a screw |d. |a wheel and axle |

____ 13. Which of the following statements about work and energy is not true?

|a. |When work is done, energy is transferred or transformed. |

|b. |Energy may be defined as the ability to do work. |

|c. |Work and energy are always equal. |

|d. |Work and energy have the same units. |

____ 14. What is the gravitational potential energy of a 55 kg box that is 8.0 m above the ground?

|a. |5500 J |c. |4300 J |

|b. |3400 J |d. |550 J |

____ 15. Gravitational potential energy depends on the

|a. |the mass of the object. |c. |the acceleration due to gravity. |

|b. |the height of the object. |d. |All of the above |

____ 16. The brakes on a car exert a frictional force of 6000 N in getting the car to stop. If the work done by the brakes is 120 000 J in coming to a stop, how many meters did the car travel after the driver applied the brakes?

|a. |6 m |c. |12 m |

|b. |20 m |d. |40 m |

____ 17. The law of conservation of energy states that

|a. |the energy of a system can disappear. |

|b. |it is impossible to make a perpetual motion machine. |

|c. |energy cannot change form. |

|d. |energy can neither be created nor destroyed. |

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