During combustion, a fuel’s electromagnetic energy is converted into thermal energy.
1 answer:
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Answer:
the work done by the lawnmower is 236.14 J.
Explanation:
Given;
power exerted by the lawnmower engine, P = 19 hp
time in which the power was exerted, t = 1 minute = 60 s.
1 hp = 745.7 watts
The work done by the lawnmower is calculated as follows;
Therefore, the work done by the lawnmower is 236.14 J.
The "penetration of the bullet" is 5 m
<u>Explanation</u>:
A "bullet" with "kinetic energy" of = 400J
A resistive force stops the bullet = 8.00 x 10 N
Work = change in energy
Work = ∆ Kinetic Energy (equation 1)
Work = (equation 2)
From equations 1 and 2 we have,
= ∆ Kinetic Energy
Where ,
Kinetic Energy = 400 J
F = 8.00 x 10 N
(8.00 x 10 N) d = 400 J
(80 N) d = 400 J
d = 5 m
The penetration of the bullet is 5 m
Complete Question
A commuter train passes a passenger platform at a constant speed of 39.6 m/s. The train horn is sounded at its characteristic frequency of 350 Hz.
(a)
What overall change in frequency is detected by a person on the platform as the train moves from approaching to receding
(b) What wavelength is detected by a person on the platform as the train approaches?
Answer:
a
b
Explanation:
From the question we are told that
The speed of the train is
The frequency of the train horn is
Generally the speed of sound has a constant values of
Now according to dopplers equation when the train(source) approaches a person on the platform(observe) then the frequency on the sound observed by the observer can be mathematically represented as
substituting values
Now according to dopplers equation when the train(source) moves away from the person on the platform(observe) then the frequency on the sound observed by the observer can be mathematically represented as
substituting values
The overall change in frequency is detected by a person on the platform as the train moves from approaching to receding is mathematically evaluated as
Generally the wavelength detected by the person as the train approaches is mathematically represented as