Answer:20.82 m
Explanation:
Given
distance between wall and launcher=5 m
initial velocity=30 m/s
Launching angle
Height of wall=12 m
maximum height by ball
h=22.95 m
y=4.72 m
so ball will strike with wall
and for perfect restitution final velocity of ball will be same as the horizontal velocity before its impact, only direction will be opposite and vertical velocity will be zero
thus it seems as if someone throw the ball with horizontal velocity of 30cos45 from a height of 4.72
Time required to cover 4.72 m
t=0.981 s
Horizontal distance traveled in this time
R=20.82 m
Assuming our "closed tube" is closed at only one end, then
<span> v = fλ = f*4L/n
</span><span> where "n" is the harmonic number. So
</span><span> L = nv / 4f = n*346m/s / 4*256Hz = n*0.38 m
</span> <span>Since the only option in your list that is an integer multiple of 0.38 m is 1.35 m
</span><span> I'd say that we're hearing the fourth harmonic.
answer is
</span><span>A. 1.35 m</span><span>
</span>
If the sign of work is negative, that means the force and the motion are in opposite directions.
Let's say you see something roll off of the shelf. You catch it, and you let it down slowly and gently.
Gravity exerted down-force on it and it moved down. Gravity did positive work on it.
YOU exerted UP-force on it and it moved down. YOU did negative work on it.
(Also, the falling object exerted down-force on your hand, and your hand moved down. The falling object did positive work on your hand ! Where did THAT energy come from ? It came from the potential energy that the object had while it was on the shelf. Your hand absorbed that energy on the way down, doing negative work. So the object didn't have any kinetic energy when it reached the floor, and it did NOT splinter the floor or shatter in smithereens. It had barely enough energy left to make a sound when it hit the floor.)
The answer is D. wavelength!
Answer:
36 km /h means 10 m/s. Increase in speed is 10m/s in 5 s . Acceleration is ( 10/5 ) = 2 m/s^ 2.
