Calculate the maximum kinetic energy of photoelectrons emitted from this plate when light of wavelength (λ) 520nm is directed at the metal surface.
work function (ф) of the plate = 1.1 × 10⁻¹⁹ j
planck's constant (h) = 6.63 × 10⁻³⁴ js
frequency (f) = c ÷ λ
c = speed light in vacuum = 3.00 × 10⁸ms⁻¹
ekmax = hf - φ
wavelength must be in metres, so it'll be 590×10⁻⁹
i've worked this out and gotten two different answers so i thought i'd check to see which one is right.

Using the free-body diagram, calculate the net force acting on the sled. is the sled in a state of dynamic equilibrium?

An ideal otto cycle has a compression ratio of 8. at the beginning of the compression process, air is at 95 kpa and 27°c, and 750 kj/kg of heat is transferred to air during the constant-volume heat-addition process. assuming constant specific heats at room temperature, determine (a) the pressure and temperature at the end of the heat-addition process, (b) the net work output, (c) the thermal efficiency, and (d) the mean effective pressure for the cycle. (4390 kpa, 1730 k; 423 kj/kg; 56.4%; 534 kpa)

The drag force, fd, imposed by the surrounding air on a vehicle moving with velocity v is given by fd = cdaρv 2/2 where cd is a constant called the drag coefficient, a is the projected frontal area of the vehicle, and ρ is the air density. an automobile is moving at v = 80 kilometers per hour with cd = 0.28, a = 2.3 m2, and ρ = 1.2 kg/m3.