A plane is flying to a city 756 km directly north of its initial location. The plane

The answer is 5.05 hours.

Explanation:

If the plane has an airspeed of 203 km/h which only applies for air and not the ground speed, we can subtract the speed of the wind since it is a headwind in the directly opposite direction.

So the speed of the plane becomes 203 - 53.5 = 149.5 km/h which will give us the true airspeed of the plane and the ground speed as well.

From here we can calculate the time it will take to reach the city as

756 km / 149.5 km/h = 5.05 hours.

I hope this answer helps.

Explanation:

A box resonate the sound hence is used in musical instruments.

While vibrations are produced by musical instruments, frequencies are created which are more enhanced in a wooden box.

For example :  Xylophone is a musical instrument that consist of wooden bars struck by mallet.

Under each bar of the xylophone there is a there is a resonator tube which amplifies the sound.

So when the wooden bars are struck, xylophones produces sound and the pitch of the sound depends on the size of the bars. Longer the bar, the more longer sound will be resonating in it hence lower will be the pitch.