Answer:
a. distance = s x t
Explanation:
The equation we know for speed is speed = distance/time, shortened to s = d/t
If you want to find the distance, you'd rearrange the formula to make d the subject. To isolate d, multiply by t on both sides (since it's being divided on the right. This leads to
s x t = d, with d isolated on the right side.
Therefore, to find the distance an object travelled you'd use a. distance = s x t
E = 0.5mv^2 = 0.5*44*10^2 = 2200J
Remember Coulomb's law: the magnitude of the electric force F between two stationary charges q₁ and q₂ over a distance r is

where k ≈ 8,98 × 10⁹ kg•m³/(s²•C²) is Coulomb's constant.
8.1. The diagram is simple, since only two forces are involved. The particle at Q₂ feels a force to the left due to the particle at Q₁ and a downward force due to the particle at Q₃.
8.2. First convert everything to base SI units:
0,02 µC = 0,02 × 10⁻⁶ C = 2 × 10⁻⁸ C
0,03 µC = 3 × 10⁻⁸ C
0,04 µC = 4 × 10⁻⁸ C
300 mm = 300 × 10⁻³ m = 0,3 m
600 mm = 0,6 m
Force due to Q₁ :

Force due to Q₃ :

8.3. The net force on the particle at Q₂ is the vector

Its magnitude is

and makes an angle θ with the positive horizontal axis (pointing to the right) such that

where we subtract 180° because
terminates in the third quadrant, but the inverse tangent function can only return angles between -90° and 90°. We use the fact that tan(x) has a period of 180° to get the angle that ends in the right quadrant.
Answer:
49.79 m/s
Explanation:
Given:
Initial velocity of the roller coaster is, 
Vertical drop or the displacement of the roller coaster is, 
The displacement is negative as the motion is in downward direction.
Now, as the motion is in vertical direction only, the acceleration of the roller coaster will be due to gravity acting in the downward direction.
So, the acceleration of the roller coaster is, 
Now, using the following equation of motion:

Where, 'v' is the velocity of the roller coaster at the bottom.
Plug in all the given values and solve for 'v'. This gives,

Therefore, the speed of the roller coaster at the bottom of the drop is 49.79 m/s.