If you use the equation F=ma and re-arrange it to get m = F/a, you'll get the total mass. Then you have to subtract the mass of the cart from the total mass to get the mass of the rock.
Thus, m = 6N over 2m/s^2. The total mass will then be 3kg. Subtracting 1kg from the total mass will then yield you 2kg, which is the mass of the rock. Hope this helps.
Here is the answer to the given question above. Based on the Raisin Cake Analogy, the two properties of distant galaxies that astronomers have to measure to show<span> that we live in an expanding universe are DISTANCE and SPEED. Hope this answers your question. Have a great day!</span>
<span>d
The mass is doubled which means that both the momentum and kinetic energy are also doubled. Also the normal force that's acting along with the coefficient of kinetic friction is also doubled. So the friction that's working to slow down the crate is doubled. So the crate will have double the kinetic energy that needs to be dissipated, but the rate of dissipation is also doubled, so the total time required to dissipate the kinetic energy is the same. And since both crates start out with the same velocity and since they'll lose energy (and velocity) at the same proportional rate, they'll take the same distance to slide to a stop.</span>
From that ragged, motley list of statements, only 'C' is true.
This problem must be solved using a sketch. I attached an illustration of the problem.
You must trace the ray that reflects from the top off the table to your eyes. This how eyesight works, light rays reflects off the objects into your eyes.
Law of reflection tells us that light ray reflects off the surface at the same angle in which it falls on it( i attached another illustration of this).
Now we can write tangens equations:
![tan(\theta)=\frac{h-0.8}{1}\\ tan(\theta)=\frac{1.8-h}{2.8}\\ \frac{h-0.8}{1}=\frac{1.8-h}{2.8}](https://tex.z-dn.net/?f=tan%28%5Ctheta%29%3D%5Cfrac%7Bh-0.8%7D%7B1%7D%5C%5C%0Atan%28%5Ctheta%29%3D%5Cfrac%7B1.8-h%7D%7B2.8%7D%5C%5C%0A%5Cfrac%7Bh-0.8%7D%7B1%7D%3D%5Cfrac%7B1.8-h%7D%7B2.8%7D)
We solve for h: