A 10 kg baby sits on a three-legged stool. The diameter of each of the stool's round feet is 1.9 cm. A 60 kg adult sits on a four-legged chair that has four circular feet, each with a diameter of 5.8 cm. Who applies the greater pressure to the floor and by how much?
An extra _______N/m2 of pressure was applied to the floor by
2007-06-25 13:52:22 · 3 answers · asked by Ciel S 1 in Science & Mathematics ➔ Physics
Child P1= m1 g / (3 pi r1^2)
Adult P2= m2 g / (4 pi r2^2)
P1/P2= m1/m2 (r2/r1)^2
P1/P2= (10/60)(5.8 / 1.9)^2 (4/3)=2.06 times a child applies more pressure than adult in this case.
Extra pressure is dP=P1-P2
dP= [g/pi] [m1/3(r1)^2 - m2/4(r2)^2] just do the math.
dP=[9.81/3.1459..][10/(3 x (1.9E-2)^2) - 60 / 4 x (5.8E-2)^2)]=
dP= 3.122( 9233.6 - 4459)
dP=14906 N/m^2
2007-06-25 13:59:36 · answer #1 · answered by Edward 7 · 0⤊ 0⤋
The baby applies 3844.075 N/m^2 on the floor and the Adult applies 13923.692 N/m^2 on the floor. So teh baby exerts 24520.383 N/m^2 more on the floor
2007-06-25 21:08:45 · answer #2 · answered by Jason 1 · 0⤊ 0⤋
P1= m1 g / (3 pi r1^2)
P2= m2 g / (3 pi r2^3)
2007-06-25 21:04:12 · answer #3 · answered by !~famous~! 2 · 0⤊ 1⤋