The fulcrum of a uniform 20-kg seesaw that is 4.0 m long is located 2.5 m from one end. A 30-kg child sits on the long end. Part A Determine the mass a person at the other end would have to be in order to balance the seesaw. Express your answer to two significant figures and include the appropriate units. m = nothing nothing

57 kg

Explanation:

Mass of seesaw = 20 kg

Length of seesaw = 4 m

Mass of child on the longer end = 30 kg

The weight of the seesaw acts at the center i.e. 2m

The algebraic sum of moments of all forces about any point is zero, hence, using the fulcrum as the reference point:

[x * 9.8* 1.5] - [20 * 9.8* (2.5 - 2)] - [30 * 9.8 * 2.5] = 0

=> 14.7x = (20*9.8*0.5) + 735

14.7x = 98 + 735

14.7x = 833

=> x = 833/14.7

x = 57 kg