Perseverance, good mind set, and work ethic
Average velocity is displacement divided by time elapsed; Δv/Δt
You will need to use the information in the table you are given. Subtract: (final velocity - initial velocity) and divide by (final time - initial time).
You need to clean and sand wood of any ruff edges
Answer:
acceleration = 45 m/s²
Time = 20 seconds
Explanation:
We are given;
Distance; s = 90m
Final velocity;v = 90 m/s
Since shot from rest, initial velocity;u = 0 m/s
So, to find the acceleration, we can use Newton's 2nd law of motion which is;
v² = u² + 2as
Where a is acceleration
Plugging in the values;
90² = 0² + 2a(90)
8100 = 180a
a = 8100/180
a = 45 m/s²
Now, for the time, we will use Newton's 1st law of motion which is;
v = u + at
Where t is time;
So;
90 = 0 + 4.5t
90 = 4.5t
t = 90/4.5
t = 20 seconds
Answer:
d = 120 [m]
Explanation:
In order to solve this problem, we must use the theorem of work and energy conservation. Where the energy in the final state (when the skater stops) is equal to the sum of the mechanical energy in the initial state plus the work done on the skater in the initial state.
The mechanical energy is equal to the sum of the potential energy plus the kinetic energy. As the track is horizontal there is no unevenness, in this way, there is no potential energy.
E₁ + W₁₋₂ = E₂
where:
E₁ = mechanical energy in the initial state [J] (units of Joules)
W₁₋₂ = work done between the states 1 and 2 [J]
E₂ = mechanical energy in the final state = 0
E₁ = Ek = kinetic energy [J]
E₁ = 0.5*m*v²
where:
m = mass = 60 [kg]
v = initial velocity = 12 [m/s]
Now, the work done is given by the product of the friction force by the distance. In this case, the work is negative because the friction force is acting in opposite direction to the movement of the skater.
W₁₋₂ = -f*d
where:
f = friction force = 36 [N]
d = distance [m]
Now we have:
0.5*m*v² - (f*d) = 0
0.5*60*(12)² - (36*d) = 0
4320 = 36*d
d = 120 [m]
