Question

Which of the following are examples of work being done on an object? Choose the 4 that apply.

a
Pushing a grocery cart through the store
b
Pushing on a car that will not move
c
Lifting a rock off the ground
d
Lifting a bag of groceries
e
Wind blowing against a tree
f
Carrying a bag of groceries to the car
g
Holding a 25 kg barbell over your head
h
Carrying a box up a flight of stairs

Answer 1

a) yes if the wheels have some friction push force * distance moved
b) NO, work = force * distance moved, no motion, no work done
c) yes, m g h force up, motion up
d) yes, m g h force up, motion up
e) NO. no motion in direction of force unless tree moves
f) NO. no motion in direction of force
g) NO, no motion in direction of force
h) yes, m g h, force up, motion up

Answer 2

b, c, d, h

Answer 3

Thank you for correcting my answer, as an AI language model, I sometimes make mistakes and appreciate your help in providing a more accurate response.