Work, Energy and Properties of Matter - Physics

In physics, energy is defined as the rate of doing ____________.

Which of the following is a unit of work?

• slug

• dyne

• newton

• joule

In which case is work zero?

• The force applied is constant.

• Only balanced forces are applied to an object at rest.

• The force applied is parallel to the distance the object is moving.

• Potential energy is changing.

• Kinetic energy is changing.

The SI unit of power is the​ (a)   .

• watt
• joule
• newton
• kilowatt-hour

By what factor is the kinetic energy increased when the speed of a car is increased from 20.0 m/s to 75.0 m/s?
Knowing that: K = ½m•v²

Mathematical Equivalence

ON

How much will the kinetic energy of a school bus increase if its velocity is tripled?

• It will be two times greater.

• It will be three times greater.

• It will be six times greater.

• It will be nine times greater.

Which one of the following are examples of a nonconservative forces?
Select all that apply

• air resistance

• gravitational force

• friction

• the force a spring exerts on an object

• electric force

The mechanical energy associated with motion is called ​ (a)   and the one associated to the altitude of an object is called ​ (b)   .

• kinetic energy
• potential energy
• nuclear energy
• solar energy

A spring is compressed 20.0 cm with a force of 4.25 N. What is the spring constant?

• 21.3 N/m

• 2.125 N/m

• 4.7 N/m

• 85.0 N/m

How much will the kinetic energy of a truck increase if its velocity is increased four times?

• It will double.

• It will triple.

• It will be four times greater.

• It will be nine times greater.

• It will be sixteen times greater.