Question

Which of the following is not an example of work, according to the scientific definition?

A. lifting a suitcase off the floor

B. leaning against a brick wall on the side of a building

C. pulling a sled across the snow

D. pushing a grocery cart

please help as soon as possible

Answer 1

It is definitely B!
Work is shown by a change in displacement (distance from point A)
Since leaning on a brick wall doesn't move it, there is no work done.

Here's a short explanation on this site:
http://www.physicsclassroom.com/class/energy/Lesson-1/Definition-and-Mathematics-of-Work

Hope that helps! I just finished physics this year and know the struggle :)

Answer 2

Thanks, could you help with some other problems?

Answer 3

@OliviaDanielle222

Answer 4

Hmm we didn't learn a lot in that class lol but I could try on some other ones :)

Answer 5

How do simple machines make work easier?

A. they change the strength or direction of a force

B. they apply force quickly

C. they decrease the power a available

D. they maintain the distance of a force

Answer 6

@OliviaDanielle222

Answer 7

Simple machines are to use the same amount of force to move a distance further. "Simple machines give us an advantage by changing the amount,
speed, or direction of forces."

This pdf has good basic desciptions:
http://camillasenior.homestead.com/review_simple_machines.pdf

...anyways it's A.

Answer 8

haha thanks,

what has changed when a gardener uses a lever to lift a rock, instead of using his hand?

A. more force is applied over a longer distance

B. less force is applied over a longer distance

C. more force is applied over a shorter distance

D. less force is applied over a shorter distance

Answer 9

lol sorry i just realized i accidentally asked this in the history section... @OliviaDanielle222

Answer 10

http://openstudy.com/study#/updates/536bf17fe4b0e4d5545d11ba

Less force is applied over a longer distance. So B.

haha someone else asked this question on here already. Hope I helped a little I'm sorry I have to go but I can do some others later if you want :)

Answer 11

okay thank you! @OliviaDanielle222