An astronaut in space cannot use a scale or balance to weigh objects because there is no gravity. but she does have devices to measure distance and time accurately. she knows her own mass is 78.4 kg, but she is unsure of the mass of a large gas canister in the airless rocket. when this canister is approaching her at 3.60 m/s, she pushes against it, which slows it down to 1.20 m/s (but does not reverse it) and gives her a speed of 2.40 m/s.

a. what is the mass of the canister?
b. how much kinetic energy is "lost" in this collision, and what happens to that energy?

Photoelectrons with a maximum speed of 6.50 x 107 m/s are ejected from a surface in the presence of light with a frequency of 6.75 x 1014hz. if the mass of an electron is 9.10 x 10-31 kg, calculate in joules the maximum kinetic energy of a single electron. 3.84 x 10-15 j 1.92 x 10-15 j 5.92 x 10-23 j 3.07 x 10-16 j

Find the steady-state temperature at the center of the plate = /2, = /2) for sums of w from n=1 to n=19 (only odd values). find the value of n for which the change in /2, /2) is less than 1% from the value at the previous n. at this point, we consider the solution converged. does the value of the temperature at the center seem reasonable? in this part, the values of x and y are constant scalar values. you should produce a plot of the value of n on the horizontal and the estimate of the temperature at the center of the plate on the vertical. b. using the value of n (or larger) that resulted in convergence in part (a), create a contourf plot of the temperature distribution across the entire plate. use enough spatial subdivisions to create a useful plot. comment on the results. hint: you need to determine what “x” and “y” values to use to make your t matrix. i recommend using a different number of x and y values. use enough x and y values so that the plot is “smooth”.

Mechanical energy is when there are no forces causing an object to lose energy. a. increased b. conserved c. decreased d. doubled i need this answer ! .