Answer:
Fa = 5000 [N]
Explanation:
To solve this problem we must use Newton's second law, which tells us that the sum of forces on a body is equal to the product of mass by acceleration.
Let's assume that the movement of the plane is to the right, any movement or force to the right will be marked with a positive sign, while any force or movement to the left, will be taken as negative.
The force of the turbine drives the plane to the right, therefore it is positive, the acceleration is constant and keeps the movement to the right, therefore it is positive, the wind drag force tries to prevent the movement of the plane to the left therefore it is negative, with this analysis we deduce the following equation.
ΣF = m*a
where:
ΣF = sum of forces [N] (units of Newtons)
m = mass = 65000 [kg]
a = acceleration = 3 [m/s²]
Fa = force exerted by the air [N]
200000 - Fa = 65000*3
Fa = 200000 - (3*65000)
Fa = 5000 [N]
We make use of the equation: v^2=v0^2+2a Δd. We substitute v^2 equals to zero since the final state is halting the truck. Hence we get the equation -<span>v0^2/2a = Δd. F = m a from the second law of motion. Rearranging, a = F/m
</span>F = μ Fn where the force to stop the truck is the force perpendicular or normal force multiplied by the static coefficient of friction. We substitute, -v0^2/2<span>μ Fn/m</span> = Δd. This is equal to
K=0.5 mu×u
K=2200J no matter the direction
Atoms diameter are on the order of 60 to 600pm (picometers). This is around 6*10^-11.
