A boy in a canoe paddles upriver at a speed of 1.4 m/s relative to the water. The water flows downriver at a speed of 1.4 m/s relative to the riverbed. How fast does the boy's canoe appear to move when viewed by an observer standing on the riverbank? A:0 m/s

B:1.4 m/s up the river

C: 1.4 m/s down the river

D: 2.8 m/s up the river

I want this solved in 5 minutes pl​

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?

Which object is most likely represented by a dot?

Suppose a wheel with a tire mounted on it is rotating at the constant rate of 2.15 times a second. a tack is stuck in the tire at a distance of 0.373 m from the rotation axis. noting that for every rotation the tack travels one circumference (a) find the tack's tangential speed. (b) what is the tacks radial acceleration?