What is the potential energy of a 25 kg bicycle resting at the top of a hill 3 m high? (Formula: PE = mgh)
2 answers:
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Here in crash test the two forces are acting on the dummy in two different directions
As we know that force is a vector quantity so we need to use vector addition laws in order to find the resultant force on it.
So here two forces are given in perpendicular direction with each other so as per vector addition law we need to use Pythagoras theorem to find the resultant of two vectors
so we can say
here given that
now we will plug in all data in the above equation
so it will have net force 4501.9 N which will be reported by sensor
<h2>Answer:</h2>
<em><u>(a). 16.741 m/s</u></em>
<em><u>(b). 15.75 m/s</u></em>
<h2>Explanation:</h2>In the question,
Height of the cliff, h = 37 m
Time taken to reach the sound to us = 2.92 s
Speed of the sound in air at room temperature = 343 m/s
Now,
Let us say the speed of the ball = u m/s
So,
Time taken by the ball to reach at the bottom, t is given by,
So,
Splash is heard after = 2.92 s
So,
<u>Time taken by sound to travel the shortest distance along the hypotenuse of the triangle</u> thus formed is,
t = 2.92 - 2.747
t = 0.172 s
Now,
Distance traveled by sound is given by,
So,
In the triangle using the Pythagoras Theorem,
Horizontal distance traveled is,
So,
Speed of throwing of ball is given by,
<em><u>Therefore, the speed of the ball = 16.741 m/s.</u></em>
(b).
If,
Speed of sound = 331 m/s
So,
<u>Distance traveled by sound</u> is,
So,
Distance traveled in the horizontal by ball is,
So,
Speed of the ball thrown is given by,
<em><u>Therefore, the speed of the ball = 15.75 m/s.</u></em>