- Homework Statement:
A man of mass 100kg wants to launch a brick into the air using a see saw.
He wants to launch the bricks of mass 5kg, 10 meters vertically in to the air.
The see saw is placed parallel to the ground using a support.
The bricks are placed on one end of the see saw.
The see saw is made of rigid material with a fulcrum in the center.
The see saw beam is 5m long
If the man jumps onto the far end of the seesaw (5 meters from the bricks) from a height of h meters from where he would land on the see saw.
Assume no air resistance, total energy convertion.
a) Find the value of h
b) What would be the value of h if the fulcrum was placed 1m from the bricks
c) what would be the value of h if the fulcrum was placed 1 m from where the man was to land.
- Relevant Equations:
Moment = force x perpendicular distance
Work done = force x distance moved
I drew a diagram for the a) part
The person is h meters high
So GPE= 100 x 9.8x h
GPE= 980h j
KE = 980h when the person hits the see saw
980h=0.5 x 5 x v²
Now it v²=u²+2as
For the brick going up to 10m
v = 0
u²=2 x 9.8 x 10
We can assume that u=14m/s is the velocity that the man is when he hits the see saw
980h = 490
I used the mass of bricks for the person
980h = 0.5 x 100 x 14²
980h = 9800
Is this correct?
I assumed that the v for both sides of the see saw is same cause the fulcrum is in the middle
But don't know how to attempt it when the fulcrum is not in the middle as in part b) and c)
Thank you in advance