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Alona [7]
3 years ago
12

A train travels 90 kilometers in 4 hours, and then 82 kilometers in 1 hours. What is its average speed?

Physics
1 answer:
kvasek [131]3 years ago
5 0
Average speed = total distance / total time.

That's 172 km / 5 hr = 34.4 km//hr
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The tip of the second hand of a clock moves in a circle of 20 cm circumference. In one minute the hand makes a complete revoluti
Cerrena [4.2K]

Answer:

v_{avg} = 0

Explanation:

As we know that average velocity is defined as the ratio of total displacement of the object and its time interval.

so here we can say

v_{avg} = \frac{displacement}{time}

now we know that in one complete revolution the total displacement of the tip of the seconds hand is zero

because it will have same position after one complete revolution from where it starts

so here we can say that the average velocity will be zero

v_{avg} = 0

7 0
3 years ago
Describe the motion of a swing that requires 6 seconds to complete one cycle. What is its period and the frequency? Round to the
shutvik [7]

Period = 6 seconds and frequency = 0.167Hz .

<u>Explanation:</u>

We have , the motion of a swing that requires 6 seconds to complete one cycle. Period is the amount of time needed to complete one oscillation . And in question it's given that 6 seconds is needed to complete one cycle. Hence ,Period of the motion of a swing is 6 seconds . Frequency is the number of vibrations produced per second and is calculated with the formula of  \frac{1}{t} . SI unit of frequency is Hertz or Hz. We know that time period is 6 seconds so frequency =   \frac{1}{t}

⇒ frequency = \frac{1}{time}

⇒ frequency = \frac{1}{6}

⇒ frequency = 0.167Hz

Therefore , Period = 6 seconds and frequency = 0.167Hz .

7 0
3 years ago
An green hoop with mass mh = 2.8 kg and radius rh = 0.17 m hangs from a string that goes over a blue solid disk pulley with mass
vladimir2022 [97]
The mass of the hoop is the only force which is computed by:F net = 2.8kg*9.81m/s^2 = 27.468 N 
the slow masses that must be quicker are the pulley, ring, and the rolling sphere. 
The mass correspondent of M the pulley is computed by torque τ = F*R = I*α = I*a/R F = M*a = I*a/R^2 --> M = I/R^2 = 21/2*m*R^2/R^2 = 1/2*m 
The mass equal of the rolling sphere is computed by: the sphere revolves around the contact point with the table. So using the proposition of parallel axes, the moment of inertia of the sphere is I = 2/5*mR^2 for spin about the midpoint of mass + mR^2 for the distance of the axis of rotation from the center of mass of the sphere. I = 7/5*mR^2 M = 7/5*m 
the acceleration is then a = F/m = 27.468/(2.8 + 1/2*2 + 7/5*4) = 27.468/9.4 = 2.922 m/s^2
6 0
3 years ago
An action potential arriving at the presynaptic terminal causes what to occur?
Ulleksa [173]

Answer:

Voltage-gated calcium ion channels open, and calcium ions diffuse into the cell

5 0
3 years ago
An Olympic runner completes the 200-meter sprint in 23 seconds. What is the runner’s average speed? (Round your answer to the ne
LUCKY_DIMON [66]
The answer that is got 8.7 . I got that because if you divide 200 by 23  you get <span>8.69565217391 and if you round that you get 8.7</span>
5 0
4 years ago
Read 2 more answers
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