In the balmer series, how many spectral lines have the wavelength greater than 400 nm?

A55-kg pilot flies a jet trainer in a half vertical loop of 1200-m radius so that the speed of the trainer decreases at a constant rate. knowing that the plane has a speed of 550 km/h at point a, and the pilot experiences weightlessness at point c (i. e., the normal force from the seat bottom is zero), determine (a) the deceleration of the plane, (b) the force exerted on her by the seat of the trainer when the trainer is at point b.

An electron and a proton are held on an x axis, with the electron at x = + 1.000 m and the proton at x = - 1.000 m. part a how much work is required to bring an additional electron from infinity to the origin? express your answer with the appropriate units. part b if, instead of the second electron coming in from infinity, it is initially at x = + 20.00 m on the axis and is given an initial velocity of 100.0 m/s toward the origin, does it reach the origin? part c how close to the origin does it come?

Consider motion in one dimension. (the sign of the vector quantities is their direction indicator.) an object moves in the positive x-direction with speed 2.9 m/s for 4.5 s. it stops for 3.8 s and then moves in the negative x direction with speed 2.8 m/s for 4 s. what is the total distance traveled by the object in units of meter? enter a number with two digits behind the decimal point.