Question

A cat named SchrÖdinger walks along a uniform plank that is 4.00 m long and has a mass of 7.00 kg. The plank is supported by two sawhorses, one that is 0.44 m from the left end of the plank, and the other that is 1.50 m from the right end. When the cat reaches the very right end of the plank, the plank starts to tip. What is Schrodinger’s mass? Note: Just when the plank begins to tip, the normal force on the plank from the sawhorse on the left will go to zero.

Answer 1

Answer:

2.3 kg

Explanation:

L = length of the plank = 4 m

M = mass of the plank = 7 kg

m = mass of cat = ?

$F_{c}$ = Weight of the cat = mg

$F_{p}$ = Weight of the plank = Mg = 7 x 9.8 = 68.6 N

ED = 2 m

CD = 1.5 m

EC = ED - CD = 2 - 1.5 = 0.5 m

Using equilibrium of torque about sawhorse at C

$F_{p}$ (EC) = $F_{c}$ (CD)

(68.6) (0.5) = (mg) (1.5)

(68.6) (0.5) = (m) (1.5) (9.8)

m = 2.3 kg