Chapter 4 quiz

A 1.5 kg object moving at 3.5 m/s has kinetic energy of?

(1/2) x 1.5 (kg) x [3.5 (m/s)]2 = 9.1875 =9.2 Joules

A student weighing 300 N climbed a flight of stairs 5.o m high in 6 s. How much work was done by the student?

1500 J

A student weighing 200 N climbs a flight of stairs 9.0 m high in 4 s. What power is required to perform this task?

200 x 9.0 /4= 450 W

A student weighting 300 N climbed a flight of stairs 5.0 m high in 6.0s. What is the power of the student?

250 W

an object of mass 2 kg has a speed of 8 m/s and moves a distance of 6 m. What is its kinetic energy in joules?

64

The potential energy of a pendulum is least

At the bottom of its swing.

Currently, in the United States, which fuel is utilized to produce the majority of electrical power?

Coal

The largest reserve of energy in the United States is in what form?

Coal

The worst emitter of mercury, which damages the nervous system, are power plants that use?

Coal

The worst emitters of mercury, which damages the nervous system, are power plants that use

Coal

An object of mass 2 kg has a speed of 8m/s and moves a distance of 6 m. what is its kinetic energy in joules?

Ek=1/2 mv2

The units of work are the same as those of _______________.

Energy

State the law of conservation of energy

Energy cannot be created or destroyed, it can only transferred from one place to another.

In changing from one form to another, energy is always ______________________.

Energy, conversion, conserved

What is the potential energy of a 20kg object that is placed on a 2.5 m high wall?

Ep= m*g*h h= 2.5m m=20 kg =20kg x 9.80m/s2 x 2.5m =490 J <======== Answer

The______________ distance in used in calculating work.

Force

Which of the following is a vector quantity?

Force

Which one of the following countries obtains the largest proportion of its electricity from nuclear energy?

France

The quantity mgh is known as

Gravitational potential energy

Which of the following sources of energy presents the fewest pollution problems under normal operating conditions?

Hydroelectric power

Currently, in the united States, which sector of the economy uses the most energy?

Industry

A 4-kg object falls vertically a distance of 5 m. Its potential energy has changed by approximately how much?

It has decreased by 200 J.

Currently, in the United States, which fuel has the largest consumption?

Oil

A student weighting 200 N climbs a flight of stairs 9.0 m high in 4 s. What work does the student do?

PE=mgh (200N) (9.0)= 1,800 J

A spinning skater whose arms are at her sides then stretches out her arms horizontally

She spins more slowly.

When the momentum of a moving object is increased, there must also be an increase in which one or more of the following of the object's properties?

Speed

Car B is traveling twice as fast as car A. They both have the same mass and travelling on a level road. Which car has the greater gravitational potential energy? Explain your answer.

They are both the Same.

A joule per second (J/S) is a

Watt

a joule per second (J/s) is a

Watt

Gravitational potential energy is equal to the _______________of an object times its height.

Weight

The product of force times parallel distance is called____________.

Work

A force of 12 N acts on a 2.0-kg object through a parallel distance of 1.5 m. How much work is done on the object?

Work is = Force x Distance 12N x 1.5m=

A system may

a. be isolated. b. have real boundaries. c. have imaginary boundaries. d. all f these <=================Correct Answer

potential-energy values may be

a. positive only. b. negative only. c. zero only. d. all of the these <=======Correct Answer

The potential energy of a pendulum is least

at the bottom of its swing

The kinetic energy of a pendulum is least

at the top of its swing

The worst emitter of mercury, which damages the nervous system, are power plants that use of the following, the energy source that likely to be used up first is

coal

Work is defined as force times

distance

If you lift a 15-N weight vertically 30 m above the ground, you are

doing work against gravity

A kilowatt-hour is a unit that measures

energy

Energy provided directly from Earth's interior is called

geothermal energy

What two energy sources, if any, cannot be traced to sunlight falling on the earth?

geothermal, and nuclear

The process by which electricity can be generated by using running or falling water is known as

hydroelectric generation

The two types of mechanical energy are _____________and _______________.

kinetic and potential

A moving object must necessarily have?

kinetic energy

Energy resulting from motion is called ______________

kinetic energy

The energy of motion is called

kinetic energy

the quantity 1/2 mv2 is known as

kinetic energy

The kinetic energy of a pendulum is ______________________at the bottom of its swing.

maximum ( or greatest)

work requires

motion

In the relatively near future, the technology most able to replace fossil fuels on a large scale is

nuclear

Of the following , the energy source that likely to last the longest

nuclear

What two energy sources, if any, cannot be raced to sunlight falling on the earth?

nuclear and geothermal

One watt is equal to _____________per second.

one joule

A major unresolved problem for nuclear energy is

permanent waste disposal

The energy of position is called

potential energy

We define the total mechanical energy of an object as

potential energy plus kinetic energy.

Almost all energy comes to and leaves the earth in the form of

radiant energy

Most of all energy comes to and leaves the earth in the form of

radiant energy

The impurity in coal the leads to acid rain is

sulfur

Power is

the rate at which work is done

Power is

work divided by time