Question

A crane lift a crate.

a. Calculate the work done if the crate weigh 500N and it is lifted 2m off the ground

b. If the crane does 5000J of work to lift the crate in 5m, how much does the crate weigh?

c. If the crane does 1000J of work to lift a crate that weighs 400N, how high does it lift the crate off the ground
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Answer 1

✰ Question :-

❪a❫ Calculate the work done by crane if the crate weigh 500N and it is lifted 2m off the ground ?

✸ Given :-

⋄Weight of crate (mg) = 500N

⋄ height (h) of crate lifted by crane =2m

✸To find :-

⋄ Work done by crane on lifting crate???

✸ Solution :-

➤ W=mgh

➤ W = 500×2

➤ W=1000J.

∴The work done by crane is 1000J.

✰ Question :-

❪b❫ If the crane does 5000J of work to lift the crate in 5m, how much does the crate weigh?

✸Given:-

⋄ Work done (w) =5000J

⋄ height (h) = 5m

✸To Find :-

⋄ Weight of crate (mg)???

✸Solution :-

➤ W=mgh

➤ 5000J=mg ×5

➤mg=5000/5

➤mg=1000N

∴The weight of the object is 1000N.

✰Question

❪c❫ If the crane does 1000J of work to lift a crate that weighs 400N, how high does it lift the crate off the ground??

✸Given:-

⋄ Work done by crane (W) =1000J.

⋄ Weight of crate (mg) = 400N

✸To Find :-

⋄ Height of crate lifted by crane ??

✸ Solution :-

➤ W=mgh

➤ 1000J=400N× h

➤ h= 1000/400

➤ h= 2.5 m

∴The height of crate lifted by crane is 2.5m