10. A safe place to use the trebuchet would be away from other buildings and people. A good example of a place would be a large field with no nearby structures.
14. Many factors need to be kept consistent throughout the experiment. One example of a variable that would need to be consistent is the weight and size of the projectile.
15. It is important to do many trials so that you can make sure that the results of each trial are nearly the same. If they are all vastly different, then it means that something has gone wrong.
Sorry I was only able to answer a few questions, but I hope these few answers help! :)
Because the object is still made of the same material
Density is not affected by the weight and shape of an object its affected by how concentrated the atoms are in a given volume
In order to measure the size of the electrical current flowing in the circuit,
the current must pass through the meter.
Answer:
The range of wavelengths of the sound is 7692.30 m and 3846.15 m
Explanation:
A bat emits pulses of sound at a frequency between 39 kHz and 78 kHz. It is required to find the range of wavelengths of this sound.
Bat uses ultrasonic waves. It moves with the speed of light.
If f = 39 kHz,

If f = 78 kHz,

So, the range of wavelengths of the sound is 7692.30 m and 3846.15 m.