A proton is put on the positive Y axis a large distance (100km) from the origin. What is the minimum speed required in the - Y direction so the proton will just reach the point (0,20) cm?

Look, you have to tell us the charge at the origin or wherever as I already told you.

0,0 is the origin

To find the minimum speed required for the proton to reach the point (0, 20) cm, we can use the principle of conservation of energy.

Given:
Initial position of the proton along the positive Y axis: 100 km (or 100,000 m)
Final position of the proton: (0, 20) cm (or 0.2 m)

First, let's calculate the gravitational potential energy at the starting position. Since the gravitational potential energy is relative to an infinite distance away, we can consider it as zero.
Initial gravitational potential energy (U_initial) = 0 J

Next, let's calculate the gravitational potential energy at the final position.
Final gravitational potential energy (U_final) = - G * (m1 * m2) / r
where G is the gravitational constant (6.674 × 10^-11 m^3 kg^-1 s^-2), m1 and m2 are the masses of the objects (proton mass and Earth mass respectively), and r is the distance between the objects (100 km + 0.2 m).

Since the proton's mass is very small compared to the Earth's mass, we can neglect the Earth's motion due to the proton. Hence, we can ignore the Earth's mass and consider the proton's mass only.

m1 = mass of proton = 1.67 × 10^-27 kg
m2 = mass of Earth = 5.97 × 10^24 kg
r = distance between objects = 100,000 m + 0.2 m = 100,000.2 m

Calculating the final gravitational potential energy:
U_final = - G * (m1 * m2) / r

Now, let's equate the initial and final energies to find the minimum kinetic energy required for the proton to reach the final position.

Initial kinetic energy (K_initial) = 0 J (since the proton is initially at rest)

Final kinetic energy (K_final) = U_final

Equating the initial and final energies:
0 J = K_final

Since the kinetic energy (K) is given by the formula K = 0.5 * m * v^2 (where m is the mass of the object and v is its velocity), we have:
0 = 0.5 * m * v^2

Simplifying and solving for v:
v^2 = 0
v = 0

Therefore, the minimum speed required for the proton to reach the point (0, 20) cm is 0 m/s. This means that the proton can remain at rest at the starting position and still reach the given point.

To find the minimum speed required for the proton to reach the point (0,20) cm, we need to calculate the gravitational potential energy and then equate it to the kinetic energy.

Here's how we can solve the problem step by step:

Step 1: Calculate the gravitational potential energy (PE) between the proton and the origin.

The gravitational potential energy can be calculated using the formula:
PE = -G * (m1 * m2) / r

In this case, the proton and origin have the same mass, so we can rewrite the formula as:
PE = -G * (m^2) / r

Where:
G = gravitational constant = 6.67 x 10^-11 m^3 kg^-1 s^-2
m = mass of the proton = 1.67 x 10^-27 kg
r = distance between the proton and the origin = 100 km = 100,000 m

Substituting the values into the formula, we get:
PE = -6.67 x 10^-11 * ((1.67 x 10^-27)^2) / (100,000)

Step 2: Calculate the value of the potential energy at the point (0,20) cm.

To find the potential energy at (0,20) cm, we need to calculate the change in potential energy, as the potential energy at the origin has been already calculated.

ΔPE = PE(0, 20 cm) - PE(origin)

Step 3: Equate the gravitational potential energy to the kinetic energy.

Since the proton will reach the point (0,20) cm, the potential energy will be converted into kinetic energy at that point.

KE = ΔPE

We know that KE can be calculated as:
KE = (1/2) * m * v^2

Where:
m = mass of the proton = 1.67 x 10^-27 kg
v = velocity of the proton

Step 4: Solve for v.

By equating the equations for KE and ΔPE, we can solve for v:
(1/2) * m * v^2 = ΔPE

Substituting the known values, we can solve for v.

Once you have performed these mathematical calculations, you can obtain the minimum speed required in the -Y direction for the proton to reach the point (0,20) cm.