A 10kg crate sits on a distant planet. The planet has the same mass as Earth, but 80% of the radius of Earth (Earth radius = 6370km.) What is the approximate weight of the object on the distant planet? A) 120N
B) 160N
C) 80N
D) 100N

One day, after pulling down your window shade, you notice that sunlight is passing through a pinhole in the shade and making a small patch of light on the far wall. you see that the patch of light seems to be a circular diffraction pattern. it appears that the central maximum is about 1 cm across and you estimate that the distance from the window shade to the wall is about 3 m. what is (a) the average wavelength of sunlight? (b) the diameter of the pinhole?

The passing of heat through a material while the material itself stays in place. a. radiation b. conduction c. convection

Find the magnetic field a distance r from the center of a long wire that has radius a and carries a uniform current per unit area j in the positive z direction.