Answer:
h f = Wf + K
where the total energy available is h f, Wf is the work function or the work needed to remove the electron and K is the kinetic energy of the removed electron
If K = zero then hf = Wf
Wf = h f = h c / λ or
λ = h c / Wf = 6.63E-34 * 3.0E8 / (3.7 * 1.6E-19)
λ = 6.63 * 3 / (3.7 * 1.6) E-7 = 3.36E-7
This would be 3360 angstroms or 336 millimicrons
Visible light = 400-700 millimicrons
Umm what are you trying to say
To convert parametric to Cartesian systems, you need to find a way to get rid of the t's.
In this case, the t's are inside trigonometric functions, so we're going to use a very famous trig identity you should memorize:

If we plug sin(t) and cos(t) into that equation only x and y variables will be left!
BUT there's one thing. The given cos(t + pi/6) has nasty extra stuff in it. However, part a gives you a tip on how to relate x and y to a nice clean cos(t)
So if we do a little rearranging:

Now we can plug these into the famous trig identity!

Do a little bit of adjustments to get that final form asked for, and you'll be able to find those integers of a and b. ;)
That's true.
Netwon's second law states that the resultant of the forces F acting on a body is equal to the product between its mass m and its acceleration a:

This means that if the net force acting on an object is different from zero (term on the left), than the acceleration of the object (term on the right) must be different from zero as well, and therefore the body is accelerating.
In particular, both F and a in the equation are vectors: this means that if the acceleration is positive, F and a have the same direction. In this problem, the acceleration is positive (because the object is speeding up), therefore the force and the acceleration have same direction.