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I need help with this problem A see-saw balances with nothing on either side. Th

ID: 1603843 • Letter: I

Question

I need help with this problem

A see-saw balances with nothing on either side. Then two children arrange themselves on the see-saw such that it balances as shown. a. Each child now moves 1 foot farther away from the fulcrum. Will the see-saw remain balanced, tip to the right, or tip to the left? Explain. b. The children return to their original positions. Each child is given a bowling ball to hold. (The bowling balls are identical.) Will the see-saw remain balanced, tip to the right, or tip to the left? Explain.

Explanation / Answer

a)

m1 = mass of child on left

r1 = distance of child on left from the fulcrum

m2 = mass of child on right

r2 = distance of child on right from the fulcrum

at equilibrium

m1 r1 = m2 r2

from the diagram ,

r1 < r2

hence m1 > m2

adding 1 ft to each r1 and r2

m1 (r1 + 1) = m2 (r2 + 1)

m1 r1 + m1 = m2 r2 + m2

since m1 r1 = m2 r2 , they cancel out

m1 = m2

which is impossible

hence the see-saw tip to left since m1 > m2

b)

m = mass of bowling ball

(m1 + m) r1 = (m2 + m) r2

m1 r1 + m r1= m2 r2 + m r2

m r1 = m r2

which is impossible

hence the seesaw tip to right

since r2 > r1