Oh what a sneaky problem !
The "range" of a projectile is how far out away from the gun it goes
before it falls to the ground.
The question is asking you: "What angle should you aim the gun
above the horizon so that the bullet doesn't go <em>any</em> distance away
from the gun, and it hits the ground exactly where the gun is "
And there are two different answers. Really sneaky !
Can you think of how you could fire the gun so that the bullet would
hit the ground right under the gun ? How about pointing the gun at
the ground ... aiming 90 degrees <em>below</em> the horizon ? That would
certainly do it. Is there another way to do it ?
How about aiming the gun straight up in the air ... 90 degrees <em>above</em>
the horizon ? Then it goes up, up, up, runs out of steam, stops rising,
starts falling, comes down, down, down, and hits the ground right where
the gun was.
As long as there's no air and no wind, the two angles are +90 degrees
and -90 degrees above the horizon.
' +90 above ' means straight up. ' -90 above ' means straight down.
<span>at maximum height the final velocity will be 0
using v=u+at and resolving vertically we get
v=0.6+(-9.81)t
v=0.6-9.81t
0=0.6-9.81t
9.81t=0.6
t=0.6/9.81
t=0.061 to 3sf
Now we need to resolve horizontally to find the horizontal distance
using s=ut+1/2at^2
However we now need the total time taken for the projectile travel and return to the ground. We can assume the time taken for the projectile to reach its maximum height and return to the ground is the same therefore
the total time is 2 x 0.061=0.122seconds. They'll be now horizontal acceleration in this case scenario therefore
Hence s=ut+1/2at^2
since a=0
s=ut
s=0.6 x 0.122
s=0.073m
</span>
Can you write the formula for kinetic energy ?
Here, let me help you:
Kinetic energy = (1/2) (mass) (speed)² .
Look at the (speed) in the formula. It's squared.
So if the speed gets multiplied by (something),
the kinetic energy gets multiplied by (something)² .
If the speed starts out at 1 m/s, but gets multiplied by 4,
then the kinetic energy gets multiplied by (4)² = 16 .
Answer:
Gauge Pressure required = 606.258 kPa
Explanation:
Water will not enter the chamber if the pressure of air in it equals that of the water which tries to enter it.
Thus at a depth of 60m we have pressure of water equals
Now the gauge pressure is given by
Applying values we get
Answer and explanation;
In 1670 Gabriel Mouton, Vicar of St. Paul’s Church and an astronomer proposed the swing length of a pendulum with a frequency of one beat per second as the unit of length.
In 1791 the Commission of the French Academy of Sciences proposed the name meter to the unit of length. It would equal one tens-millionth of the distance from the North Pole to the equator along the meridian through Paris.It is realistically represented by the distance between two marks on an iron bar kept in Paris.
In 1889 the 1st General Conference on Weights and Measures define the meter as the distance between two lines on a standard bar that made of an alloy of 90%platinum with 10%iridium.
In 1960 the meter was redefined as 1650763.73 wavelengths of orange-red light, in a vacuum, produced by burning the element krypton (Kr-86).
In 1984 the Geneva Conference on Weights and Measures has defined the meter as the distance light travels, in a vacuum, in 1299792458⁄ seconds with time measured by a cesium-133 atomic clock which emits pulses of radiation at very rapid, regular intervals.