What is the formula for this type of problem?

Question

A 76 kg solid cylinder, 2.0 m long and with an end radius of 5.0 cm, stands on one end. How much pressure does it exert?

____kPa

Thanks

Answer 1

Pressure = force / area;  Force = mass x acceleration

P = (76 kg)(9.81 m/s^2) / [(pi)(0.05m)^2]

P = 745.6 N / 0.007854 m^2

P = 94.9 kPa

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You are not even close on the area!  314 square meters is the size of a large room; this cylinder is only 10 cm diameter!

Answer 2

Pressure (Pascal)   =   Force (Newtons) / Area (metre^2)

The force is the weight of the cylinder, and the area is the cross sectional area of its circular end

Weight   =   mass  x  g

               =   76   x   9.81     =     745.6 N

Cross sectional area   =   pi * r^2

                                       =    3.14159  * ( 5 x 10^-2)^2

                                        =    7.85  x 10^-3

Pressure   =   745.6 / 7.85 x 10^-3   =   9.498 x 10^ 4 Pascal

        Say     =  95 KPa