Posted by Anonymous on .
I have a few physics questions:
1. How much mechanical work is done by a weightlifter holding a mass of 100 kg, 2.0m above the floor for 3.0 s? Explain ur answer.
2. Calculate the force needed to do 2.0 kJ of work to push a load of bricks 10m?
3. A carpenter applied a force of 60N horizontally to push a plane 40cm along a piece of wood, how much work does he do?
4. A librarian does 8.0J of work to stack five identical books on top of each other. If each book has a thickness of 4.0cm what is the mass of each book?

Phyics help 
bobpursley,
It appears you are posting several questions under different names. Sorry.

Phyics help 
deepti,
you don't understand i don't get this unit and i'm failling this unit miserabely really need help

Phyics help 
bobpursley,
Show your work. I will be happy to critique your work and thinking.

Phyics help 
deepti,
ok so here's how i thought i would have to solve these:
1. W=mgh
=100*9.8*2.0
or w=0 because u lift the mass upards and carry it (perpenticular ) hence w=0
2. W=f delta D
W/D=Force
3. W=60N * 40cm (ordo i convert 40 cm to kg)
4. W=mgh
W/h=m (do i convert 4.0 cm to kg?)