Unit Test — Unit test Answers

Tracy makes a list of energy transformations that occur as an engine runs to power a car.1. Chemical energy transforms into thermal energy.2. Thermal energy transforms into electrical energy.3. Chemical energy transforms into gravitational potential energy.4. Thermal energy transforms into kinetic energy.

What is the sequence of energy transformations associated with a hydroelectric dam?

Irving, a cat, has a favorite toy that is made up of a squeaky ball at the end of a string. The toy makes up a closed system. Irving’s owner dangles the toy so that the ball swings down and then swings back up again.

Which best identifies the requirements for work to be performed?

For a group class project, students are building model roller coasters. Each roller coaster needs to begin at the top of the first hill, where a horizontal spring that is initially compressed 0.25 m will push a small car forward.Each group of students will choose a car and a spring to push the car and then build a track. The assignment is to make the car go 5.0 m/s when it reaches the bottom of the first hill. Four groups of students choose springs and build tracks as described in the table.Which group’s roller coaster will most likely make the car travel closest to 5.0 m/s when it is at the bottom of the first hill?

Lester prepares to lift a heavy sack of flour into a customer’s shopping cart. During which part of the action does Lester do work?

elastic potential energygravitational potential energyspring displacementspring constant

What is the potential energy of a spring that is compressed 0.65 m by a 25 kg block if the spring constant is 95 N/m?

A 5,400 W motor is used to do work. If the motor is used for 640 s, about how much work could it do?

What is the unit for work?

An eagle that has a mass of 4.5 kg is spotted 5 m above a lake. It flies up to its nest in a tree at a height of 25 m.

A 20.0 kg object is at rest, and then speeds up to 16.0 m/s. How much work was done on this system?

In which scenario is the least amount of work done on a crate?

A blender takes in 180 J of electrical energy. Of the 180 J, 90 J are transformed into kinetic energy, 60 J are transformed into thermal energy, and the rest is transformed into sound.

Which factor affects elastic potential energy but not gravitational potential energy?

Lamar writes several equations trying to better understand potential energy.

Energy can be changed from one form to another. Which terms can be used to describe these changes? Check all that apply.energy conversionenergy conservationenergy correlationenergy transformationenergy transference

Four vehicles are traveling on the same road. Which vehicle most likely has the greatest kinetic energy?

What is the kinetic energy of a 620.0 kg roller coaster moving with a velocity of 9.00 m/s? Round to 3 significant figures.

Which equation shows the correct relationship between mechanical energy, kinetic energy, and potential energy?