1) 
We can solve this part by using Newton's second law:
(1)
where
F is the net force
m is the mass
a is the acceleration
There are two forces acting on the boat:
forward
backward
So the net force is

We know that the mass of the boat is
m = 1177.5 kg
So we can now use eq.(1) to find the acceleration:

2) 161.0 m
We can solve this part by using the following suvat equation:

where
s is the distance travelled
u is the initial velocity
t is the time
a is the acceleration
Here we have
u = 0 (the boat starts from rest)

Substituting t = 17.7 s, we find the distance covered:

3) 18.2 m/s
The speed of the boat can be found with the following suvat equation

where
v is the final velocity
u is the initial velocity
t is the time
a is the acceleration
In this case we have
u = 0 (the boat starts from rest)

And substituting t = 17.7 s, we find the final velocity:

And the speed is just the magnitude of the velocity, so 18.2 m/s.
Use Coulomb law: F = k * q1*q2 / (r^2), where k = 9.00 * 10^9 N.m^2/C^2
F = 9.00 * 10^9 N.m^2/C^2 * 2.4*10^-8 C * 1.8*10^-6 C / [0.008m]^2 = 38.88 * 10^ -5 N
F = 39 * 10 -5N
Answer:
254 °C
Explanation:
The average kinetic energy of gas molecules K = 3RT/2N where R = gas constant = 8.314 J/mol-K, N = avogadro's constant = 6.022 × 10²³ atoms/mol
T = temperature in Kelvin.
Let K be its average kinetic energy at t = -19°C = 273 + (-19) = 273 - 19 = 254 K = T. K = 3RT/2N = 3 × 8.314 J/mol-K × 254 K/(2 × 6.022 × 10²³ atoms/mol) = 5.26 × 10⁻²¹ J
When its average kinetic energy doubles, it becomes K₁ = 2K = 2 × 5.26 × 10⁻²¹ = 10.52 × 10⁻²¹ J at temperature T₂. So,
K₁ = 3RT₁/2N
T₁ = 2NK₁/3R
T₁ = 2 × 6.022 × 10²³ atoms/mol × 10.52 × 10⁻²¹ J/3 × 8.314 J/mol-K = 508 K
The temperature difference is thus ΔT = T₁ - T = 508 K - 254 K = 254 K.
Since temperature change in kelvin scale equals temperature change in Celsius scale ΔT = 254 °C
So, we need to change the temperature of the air by 254 °C to double its average kinetic energy.
Between B and C, the object was going at a constant velocity; it is going 60 m/min consistently for that time frame.

Hi Pupil Here's Your Answer ::
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Pressure is defined as the force acting perpendicular on an unit area of the surface.
OR
The thrust per unit area is called Pressure.
let us see, on what factors the pressure depends?
Take a pin having a pointed end and a nail having blunt end. Press then against a cardboard by applying the same force. We find that the pin penetrates deep into the cardboard then the nail. In this case, force acting on two points of the cardboard is same but the area under the tip of the Pin is less than under the tip of the nail.
The effect of the forces of the scene magnitudes on the different area is different.
Conclusions : Pressure acting on the surface is inversely proportional to the area of the surface on which force acts.
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Hope this helps