Answer:
ρ = 1.13 10⁴ km/m³
Explanation:
For this exercise we use Newton's equilibrium equation
B –W + W_scale = 0
Where B is the thrust and W_scale is the balance reading
The push is given by Archimedes' law
B = ρ_water g V
B = W- W_scale
B = m g - m_scale g
Let's calculate
B = 14.7 9.8 - 13.4 9.8
B = 12.74 N
ρ_water g V = 12.74
V = 12.74 / ρ_water g
V = 12.74 / 1000 9.8
V = 0.0013 m³
Let's use density
ρ = m / V
We replace
ρ = 14.7 / 0.0013
ρ = 1.13 10⁴ km/m³
The work done on the car is -20 J.
Work done on the car is negative, meaning that the car actually does work on the external system.
<h3>Energy and law of conservation of energy</h3>
- Energy is the ability to do work
- the law of conservation of energy states that the total energy in a system is conserved
From the law of conservation of energy, the initial energy of the car before it moves down the road remains constant or unchanged.
- Initial energy = 100 J
- Initial energy = Final energy - work done on car
- Final Energy = Work done on car + initial energy
80J = Work done on car + 100 J
Work done on car = 80 - 100J
Work done on car = -20 J
Hence, the work done on the car is -20 J
Work done on car is negative.
Since work done on the car is negative, it means that the car actually does work on the external system. Hence, the decrease in the energy of the car.
Learn more about energy and work at: brainly.com/question/13387946
Answer:
2,54 cm are equal to 1 inch
Explanation:
Doing the conversion:
![55[cm]*\frac{1[inch]}{2,54[cm]} =21,65[inch]](https://tex.z-dn.net/?f=55%5Bcm%5D%2A%5Cfrac%7B1%5Binch%5D%7D%7B2%2C54%5Bcm%5D%7D%20%3D21%2C65%5Binch%5D)
<span>You can use the equation
V_xf = V_xi + a_x(t)
V_xf = 20.0m/s
V_xi = 0m/s
ax = 2.0
t
Thus, solve for t and get 10seconds
and then take 5 seconds to break after 20 seconds of driving
so for
a) 10 + 20 + 5 = 35 seconds
</span><span>for part b)
You can use the formula
Delta x/Delta t = average velocity
Need to find xf, knowing xi = 0
Thus, use the formula
x_f = x_i + V_xi(t) + (1/2)a_x(t)^(2)
x_f = 0 + 0(10) + (1/2)(2.0)(10)^(2)
x_f = 100m
so for the first 10 seconds the truck traveled 100ms
At a speed of 20m/s
20m/s = xm/20s
20*20 = x
x = 400
thus we have 100+400 = 500m
then it slows down from 500m to x_f
thus I use the equation
x_f = x_i + (1/2)(V_xf + V_xi)t
x_f = 500 + (1/2)(0 + 20)(5)
x_f = 500 + 50
x_f = 550
therefore the total distance traveled is 550m
</span>
<span>to calculate average velocity
550/35 = 16m/s
thus
V_xavg = 16m/s</span>