A worker lifts 24 bricks, each of mass 2.2 kg, onto a platform 3.5 m above the ground…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A worker lifts bricks, each of mass , onto a platform above the ground. How much work does the worker do against gravity? ()
Need a reminder? The key ideaShow
Lifting at a steady speed needs a force equal to the weight , so with . Only the height counts, not the path. Pulling along level ground at a steady speed: , with the friction force.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Mass. .
Step 2. Work. .
Answer: about .
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