The coefficient of kinetic friction between an object and the surface upon which it is sliding is 0.46. The weight of the object is 90N. What is the force of friction?

Apulley with mass mp and a radius rp is attached to the ceiling, in a gravity field of 9.81 m/s2 and rotates with no friction about its pivot.

The least penetrating form of radiation is

The number of passengers who arrive at the platform of a subway station for the 10 am train is a random variable with a mean of 120 and a variance of 16. find the lower bound of the probability that there will be between 100 and 140 passengers (round off to second decimal place).