What causes a bolt of lightning?

a. electrical charges build up in the clouds only.
b. electrical charges build up on the ground only.
c. electrical charges build up in the clouds and on the ground.
d. electrical charges build up in the space between the clouds and the ground.

A150 w lamp emits light of wavelength 590 nm uniformly in all directions. what is the photon flux (photons per unit area per unit time) on a small screen at a distance 2.3 m from the lamp? assume the photons are uniformly distributed over the surface of a sphere of radius 2.3 m.

Aparticle of mass m is projected with an initial velocity v0 in a direction making an angle α with the horizontal level ground as shown in the figure. the motion of the particle occurs under a uniform gravitational field g pointing downward. (a) write down the lagrangian of the system by using the cartesian coordinates (x, y). (b) is there any cyclic coordinate(s). if so, interpret it (them) physically. (c) find the euler-lagrange equations. find at least one constant of motion. (d) solve the differential equation in part (c) and obtain x and y coordinates of the projectile as a function of time. (e) construct the hamiltonian of the system, h, and write down the hamilton’s equations (canonical equations) of motion.

2. -/1 pointsserpse10 2.7.p.017.mi. an object moving with uniform acceleration has a velocity of 14.0 cm/s in the positive x direction when its x coordinate is 2.97 cm. if its x coordinate 2.85 s later is -5.00 cm, what is its acceleration? cm/s2 need ? read it master it