Electron’s mass is so small, it can be considered negligible
Answer:
The velocity of sound of an echo is given as:
v = 2d/t, where d is the distance the sound source and the reflecting surface.
The time take for the stroke to be heard is 2s, because the rate is one stoke per second(one stroke in 1s). It means it will be heard after 2s, after the reflection of the sound wave.
v is speed of sound in air(Value 240m/s)
Therefore, d = vt/2 = (340 x 2)/2
d = 340m.
Sally is 340m away.
Explanation:
The above question is an application of echo.
Echo is a sound heard after the reflection of sound wave.
The distance covered will be twice the distance between the source of the sound and the reflecting surface. This is because the sound will travel a certain distance to a reflecting surface and travels back equal distance to the source after getting reflected.
The car’s velocity as a function of time is b + 2ct and the car’s average velocity during this interval is 0.9 m/s.
<h3>Average velocity of the car</h3>
The average velocity of the car is calculated as follows;
x(t) = a + bt + ct2
v = dx/dt
v(t) = b + 2ct
v(0) = -10.1 m/s + 2(1.1)(0) = -10.1 m/s
v(10) = -10.1 + 2(1.1)(10) = 11.9 m/s
<h3>Average velocity</h3>
V = ¹/₂[v(0) + v(10)]
V = ¹/₂ (-10.1 + 11.9 )
V = 0.9 m/s
Thus, the car’s velocity as a function of time is b + 2ct and the car’s average velocity during this interval is 0.9 m/s.
Learn more about velocity here: brainly.com/question/4931057
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Correction
One food calorie is not 103 calories, rather, 1000 calories
Answer:
4.2 km
Explanation:
One food calorie is equal to 1000 calories and each calorie has 4.184 J hence for 617 food calories, the energy is equal to 617*1000*4.184
This energy is also given by mgh, the potential energy. M is the mass, g is acceleration due to gravity and h is height in metres.
Substituting 62.7 kg for m, 9.8 for g then
62.7*9.8h=617*1000*4.184