Question

Calculate (use the formula) how much work was done to lift a 1,000 kg block to the top of the Great Pyramid, 146 m above ground?

Answer 1

Given :-

• Mass of the block = 1000 kg

• Height of the block raised = 146 m

To Find :-

• The work done to lift the block.

Formula used -

• Potential energy

Solution :-

Here we are given the mass and height of the block. Using the formula of potential energy, we will Solve this problem. For potential energy, we should be provided with the mass of an object, height. Let's do it!

Potential energy = Mass × Gravity × Height

We know that,

Potential energy = Work done

Where,

PE = Potential energy

m = Mass

g = Gravity

h = Height

w = Work done

Consider gravity = 10 m/s

On substituting the values -

w = 1000 × 10 × 146

w = 10000 × 146

w = 1460000 J

$\implies$ 1.46 × 10⁶ J

$\therefore$ the work done by the block is 1.46 × 10⁶ Joules.

___________________________________________________________

Answer 2

$\Large\bf{\color{indigo}GiVeN,}$

• Mass of a block is 1000 kg.

• Height of the block from above the ground is 146 m.

$\bf\purple{We\:know\:that,}$

$\red\bigstar\:\:{\green{\boxed{\bf{\color{peru}Work\:done\:(W)\:=\:F\:.\:S\:}}}}$

━─━─━─━─━─━─━─━─━─━─━─

$\bf\pink{Where,}$

• F is the force acting by gravitational acceleration on the block towards downward, i.e. (mass × g).

$\longmapsto\:\:\bf\orange{F\:=\:mass\times{g}\:=\:m\:g\:}$

• S is the displacement of the block, i.e. the height from above the ground.

$\longmapsto\:\:\bf\blue{S\:=\:Height\:(h)\:=\:146\:m\:}$

━─━─━─━─━─━─━─━─━─━─━─

$:\implies\:\:\bf{W\:=\:(m\:g)\:h\:}$

$:\implies\:\:\bf\green{W\:=\:m\:g\:h\:=\:\triangle{U}}$

$\bf\pink{Where,}$

• ΔU is the change in potential energy of the block, i.e. Work done by the block is the change in potential energy.

$:\implies\:\:\bf{W\:=\:1000\times{10}\times{146}\:}$

$:\implies\:\:\bf{\color{olive}W\:=\:146\times{10^4}\:Joules}$

$\Large\bold\therefore$ The work done by the block is 146 × 10⁴ J.