A doctor at a local hospital is interested in estimating the birth weight of infants. How large a sample must she select if she desires to be 98% confident that the true mean is within 2 ounces of the sample mean? The standard deviation of the birth weights is known to be 5 ou...
Push against the rock= (mg)\(u1+u2)
A 56 kg rock climber is climbing a "chimney" between two rock slabs as shown in the figure. The static coefficient of friction between her shoes and the rock is 1.02; between her back and the rock it is 0.70. She has reduced her push against the rock until her back a...
force of push = (mg)/(u1+u2), so (49*9.8)/(1.2+.8)=240.1N fraction of weight= (u1)/(u1+u2),so (1.2)/(1.2+.8)=.6