The objective lens in a microscope with a 17.0 cm long tube has a magnification of -50.0 and the eyepiece has a magnification of 20.0. (a) what is the focal length of the objective? cm (b) what is the focal length of the eyepiece? cm (c) what is the overall magnification of the microscope?

The radioactive isotope of lead, pb-209, decays at a rate proportional to the amount present at time t and has a half-life of 3.3 hours. if 1 gram of this isotope is present initially, how long will it take for 80% of the lead to decay? (round your answer to two decimal places.)

Question 1(multiple choice worth 2 points) in order to be considered work, the components that must be present are • a force and a movement in the same direction as the force an action which causes movement and an opposite reaction an action which causes no movement or reaction a force and a movement in the opposite direction of the force

A60-kg box is being pushed a distance of 6.8 m across the floor by a force p with arrow whose magnitude is 162 n. the force p with arrow is parallel to the displacement of the box. the coefficient of kinetic friction is 0.24. determine the work done on the box by each of the four forces that act on the box. be sure to include the proper plus or minus sign for the work done by each force. (the floor is level and horizontal. forces that act on the box: pushing force p, frictional force f, normal force n, and weight mg.)