Answer:
<em>The average speed of the train is 45 km/h</em>
Explanation:
<u>Speed</u>
It's defined as the distance (d) per unit of time (t) traveled by an object. The formula is:
Let's call x the total distance covered by the train. It covered d1=1/3x with a speed of v1=25 km/h. The time taken is calculated solving for t:
Now the rest of the distance:
d2 = x - 1/3x = 2/3x
Was covered at v2=75 km/h. Thus the time taken is:
The total time is:
Simplifying:
The average speed is the total distance divided by the total time:
Simplifying:
The average speed of the train is 45 km/h
Complete question:
A 45-mH ideal inductor is connected in series with a 60-Ω resistor through an ideal 15-V DC power supply and an open switch. If the switch is closed at time t = 0 s, what is the current 7.0 ms later?
Answer:
The current in the circuit 7 ms later is 0.2499 A
Explanation:
Given;
Ideal inductor, L = 45-mH
Resistor, R = 60-Ω
Ideal voltage supply, V = 15-V
Initial current at t = 0 seconds:
I₀ = V/R
I₀ = 15/60 = 0.25 A
Time constant, is given as:
T = L/R
T = (45 x 10⁻³) / (60)
T = 7.5 x 10⁻⁴ s
Change in current with respect to time, is given as;
Current in the circuit after 7 ms later:
t = 7 ms = 7 x 10⁻³ s
Therefore, the current in the circuit 7 ms later is 0.2499 A
The distance travel is 69.5 meters.
<u>Explanation:</u>
Given datas are as follows
Speed = 27.8 meters / second
Time = 2.5 seconds
The formula to calculate the speed using distance and time is
Speed = Distance ÷ Time (units)
Then Distance = Speed × Time (units)
Distance = (27.8 × 2.5) meters
Distance = 69.50 meters
Therefore the distance travelled is 69.50 meters.
-- Coal
-- Oil
-- Natural gas
-- Falling water
-- Sunlight
-- Nuclear fission of Uranium
<h2>Answer:</h2>
<u>Acceleration is </u><u>-10.57 rad/s² </u>
<u>Time is </u><u>6 seconds</u>
<h2>Explanation:</h2><h3>a) </h3>
u=900rpm= 94.248 rad/s
v =300rpm= 31.416 rad/s
s=60 revolutions= 377 rad
v²= u²+ 2as
31.416² = 94.248²+ 2 * a * 377
a = v²-u² / 2s
a= -10.57 rad/s²
<h3>b) </h3>
Using 1st equation of motion
v-u/a = t
Putting the values
t = (31.4 - 94.2)/-10.57
t = 6 seconds
