Answer:
For example, 1300 with a bar placed over the first 0 would have three significant figures (with the bar indicating that the number is precise to the nearest ten).
Explanation:
hope it helps :)
A)
It is a launch oblique, therefore the initial velocity in the vertical direction is zero. Space Hourly Equation in vertical, we have:
Through Definition of Velocity, comes:

B)
Using the Velocity Hourly Equation in vertical direction, we have:
The angle of impact is given by:

If you notice any mistake in my english, please let me know, because i am not native.
Scientists conduct experiments in order to prove a theory or a prediction they have or contradict it, so that then they can write down their results to study them.
The frequency increasing makes the crests pass more quickly. Frequency is a count of how many times per second an event occurs. In waves, this event is the passing of an entire cycle. Once the cycle has passed, the wave repeats. The faster the wave repeats, the higher the frequency. For this reason, frequency has units of hertz, Hz. The unit of hertz is 1/s or "per second"