The question is missing, however, I guess the problem is asking for the value of the force acting between the two balls.
The Coulomb force between the two balls is:

where

is the Coulomb's constant,

is the intensity of the two charges, and

is the distance between them.
Substituting these numbers into the equation, we get

The force is repulsive, because the charges have same sign and so they repel each other.
Answer:
The two brothers working together will take 7.7 hours to dig the entire ditch.
Explanation:
Assuming T to be the total amount of time taken by both brothers working together, we can say
- 1/T ditch/hour to be the rate at which both brothers dig the ditch together
- 1/14 ditch/hour to be the rate at which the older brother digs the ditch
- 1/17 ditch/hour to be the rate at which the younger brother digs the ditch
So the rate at which both brothers dig the ditch can be calculated by the equation,
1/T = 1/14 + 1/17
T = 238/31 = 7.7 (rounded off to the nearest tenth)
Answer:
x = 7226.94 m
y = 1677.4 m
Explanation:
This is a classic problem of a parabolic move. Let's analyze the given data.
The speed is 300 m/s but it's fired at 55°, so the x and y component of the speed would be:
Vx = 300 cos55 = 172.07 m/s
Vy = 300 sin55 = 245.75 m/s
Now, to get the x and y components of the shell, we need to apply the following expressions:
X = Xo + Vx*t (1)
Y = Yo + Vy*t - 1/2 gt² (2)
Xo and Yo is 0, and we already have the speed in x and y, so the components are:
X = 0 + (172.07)(42)
<h2>
X = 7226.94 m</h2>
For the y component:
Y = 0 + (245.75)(42) - 1/2 (9.8)(42)²
Y = 10321.5 - 8643.6
<h2>
Y = 1677.4 m</h2><h2>
</h2>
Hope this helps
Answer:

2) S(Δt)=So+g(Δt)
Explanation:
I think the equation they gave you for the Height upon time in seconds it's (1), where if you see, you will find the gravity, that you should multiply by 2 because, its divided by two in (1) (that should be your (a)), then, once you find your gravity, you can use the equation (2) to know the Final Speed replacing g , at the time asked, remember that g is gravity, and Δt is the: final time- initial time.
so in the [1,2] interval of time, your Δt=1s, and in [1,1.5] is Δt=0,5s.
i hoped it helped you even though i cant give you the exact answer right now.
B = 53°
Reason: Opposite angles
A = 37°
Reason: Sum of angels on a straight line = 180 so 180-90-53 = 37°
C = 90°
Reason: Right angles = 90°
D = 37°
Reason: Sum of angels on a straight line = 180 so 180-90-53 = 37°