Answer:
t_total = 23.757 s
Explanation:
This is a kinematics exercise.
Let's start by calculating the distance and has to reach the limit speed of
v = 18.8 m / s
v = v₀ + a t₁
the elevator starts with zero speed
v = a t₁
t₁ = v / a
t₁ = 18.8 / 2.40
t₁ = 7.833 s
in this time he runs
y₁ = v₀ t₁ + ½ a t₁²
y₁ = ½ a t₁²
y₁ = ½ 2.40 7.833²
y₁ = 73.627 m
This is the time and distance traveled until reaching the maximum speed, which will be constant throughout the rest of the trip.
x_total = x₁ + x₂
x₂ = x_total - x₁
x₂ = 373 - 73,627
x₂ = 299.373 m
this distance travels at constant speed,
v = x₂ / t₂
t₂ = x₂ / v
t₂ = 299.373 / 18.8
t₂ = 15.92 s
therefore the total travel time is
t_total = t₁ + t₂
t_total = 7.833 + 15.92
t_total = 23.757 s
Answer:
- a.
- b.
Explanation:
<h3>
a.</h3>
The equation for the voltage V of discharging capacitor in an RC circuit at time t is:
where 
is the initial voltage, and 
is the time constant.
For our problem, we know
and
So
This gives us
and this is the time constant.
<h3>
b.</h3>
At t = 18.8 s we got:
new discoveries lead to new research.
Lise Meitner split the nucleus => nuclear energy research
Answer:
T_final = 279.4 [°C]
Explanation:
In order to solve this problem, we must use the following equation of thermal energy.
where:
Q = heat = 9457 [cal]
m = mass = 79 [g] = 0.079 [kg]
Cp = specific heat = 0.5 [cal/g*°C]
T_initial = initial temperature = 40 [°C]
T_final = final temperature [°C]
![9457 = 79*0.5*(T_{f}-40)\\239.41=T_{f}-40\\\\T_{f}=279.4[C]](https://tex.z-dn.net/?f=9457%20%3D%2079%2A0.5%2A%28T_%7Bf%7D-40%29%5C%5C239.41%3DT_%7Bf%7D-40%5C%5C%5C%5CT_%7Bf%7D%3D279.4%5BC%5D)
Answer:
1716.75 J
Explanation:
<u>Step </u><u>1</u><u>:</u> First check what we are provided with. As per given question we have:
mass (m) = 70 kg, height (h) = 2.5 m and acceleration due to gravity (g) = 9.81 m/s².
<u>Step</u><u> </u><u>2</u><u>:</u> Check what we are asked to find out.
Work done = Change in Potential energy
The stuff required to solve this question is potential energy. Using the formula: P = mgh. Where P is Potential energy, m is mass, g is acceleration due to gravity and h is height.
<u>Step</u><u> </u><u>3</u><u>:</u> Substitute the known values in the above formula.
→ P = 70 × 2.5 × 9.81
→ P = 1716.75 J
Hence, the work done against the force of gravity is 1716.75 J.
