Unit Test — Unit test Answers

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 535 kg roller coaster car began at rest at the top of a 93.0 m hill. Now it is at the top of the first loop-de-loop.This roller coaster’s track is nearly frictionless, so resistance can be ignored. Using g = 9.8 m/s2, what best describes the roller coaster car when it is at the top of the loop-de-loop?

Examine the scenarios.Scenario W: A force of 75 N moves a box 15 m.Scenario X: A force of 100 N moves a box 12 m.Scenario Y: A force of 50 N moves a box 20 m.Scenario Z: A force of 25 N moves a box 45 m.

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?

Natalia lifts a bag of groceries 0.50 m by exerting a force of 36 N. How much work did she do on the bag?

Hiro walks up a flight of stairs in his apartment building. Later in the day, he runs up the same flight of stairs.

How is power calculated?

Efficiency is the ratio of output work to input work, expressed as a percentage. Light bulbs put out less light energy than the amount of electrical energy that is put into the bulb.

When an object is not in motion, it can still have a form of energy. What form of energy does an object have due to its distance from Earth?

Which formula can be used to find velocity if kinetic energy and mass are known?

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.

According to the work-energy theorem, the amount of work done can be determined using which formula?

kinetic potentialgravitationalwork

A toy plane has a mass of 2.5 kg and is 18 m above the ground. It is moving at 4.5 m/s.

Which best identifies the requirements for work to be performed?

An object that is 0.5 m above the ground has the same amount of potential energy as a spring that is stretched 0.5 m. Each distance is then doubled.

What does it mean when work is positive?

What term is used to describe a system that loses energy to objects that are not part of the system?