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! :)
Answer:
1800 meters
Explanation:
Average speed=1.2 m/s
time= 1500 secs
Displacement = average speed × time
= 1.2 × 1500
=1800 meters
Answer:

Explanation:
We can solve the problem by using the following suvat equation:

where
v is the final velocity
u is the initial velocity
a is the acceleration
s is the displacement
For the car in this problem:
u = 0 (it starts from rest)
is the final velocity
s = 10 km = 10 000 m is the displacement
Solving for a, we find:

Answer:
Group 1 - the alkali metals. The Group 1 elements in the periodic table are known as the alkali metals.
Explanation: