Answer:
The image will most likely be 20cm in front the mirror since the mirror was placed further 5cm.
The molecules which evaporate presumably take heat away from the liquid. So, I'd disagree with the classmate. Whether the amount of cooling would differ from the usual case wherein the molecules have different speeds is another question.
I guess the argument goes something along the lines of that the faster moving and therefore most kinetically energetic molecues evaporate and take away most heat. But if there's no faster moving molecules, 'cos they all have the same speed well, then presumably they'd all take away the same amount of heat. So, maybe the cooling would be less. No cooling though ??? Hmmmm dunno .... i think not ....
Answer:
Velocity,v = 0.323 m/s
Explanation:
The acceleration of a particle is given by :
b = 0.8 m when x = 0
Since, 
![\dfrac{v^2}{2}=-[0.1x-0.8cos\dfrac{x}{0.8}]+c](https://tex.z-dn.net/?f=%5Cdfrac%7Bv%5E2%7D%7B2%7D%3D-%5B0.1x-0.8cos%5Cdfrac%7Bx%7D%7B0.8%7D%5D%2Bc)
At x = 0, v = 1 m/s
![\dfrac{v^2}{2}=-[0.1x-0.8cos\dfrac{x}{0.8}]-0.3](https://tex.z-dn.net/?f=%5Cdfrac%7Bv%5E2%7D%7B2%7D%3D-%5B0.1x-0.8cos%5Cdfrac%7Bx%7D%7B0.8%7D%5D-0.3)
At x = -1 m
v = 0.323 m/s
So, the velocity of the particle is 0.323 m/s. Hence, this is the required solution.
Kinetic Energy is defined by Ke=1/2mv^2. Plug in and solve for v.
2,000 = 1/2(1000)(v)^2
4=(v)^2
v=2 m/s
The car must move at 2 m/s to have a Ke of 2,000 Joules.
