Answer:
V=14.9 m/s
Explanation:
In order to solve this problem, we are going to use the formulas of parabolic motion.
The velocity X-component of the ball is given by:

The motion on the X axis is a constant velocity motion so:

The whole trajectory of the ball takes 1.48 seconds
We know that:

Knowing the X and Y components of the velocity, we can calculate its magnitude by:

<span>So we want to know what will happen when the fast moving car that is making loud noise that is initially approaching the person, passes the person and starts to move away. So Doppler effect is a phenomenon where when the source of a sound is approaching a person, the person hears the sound as higher than if the source was standing still with respect to the person because the wavelength is getting shorter, and as the source is moving avay from the person the sound is getting deeper because the wavelength is getting longer. So the correct answer is A. </span>
Answer:
The pressure must have increased in the process
Explanation:
The State Equation for gasses reads: 
where P is the gas' pressure, V its volume, n the number of moles of gas, R the gas constant and T the temperature in degrees Kelvin.
If the temperature of the gas doesn't change in the described process, the right hand side of the equation stays the same. If that is the case, given that when the Volume of the gas diminishes from 75 liters to 50 liters, then the pressure must have increased to keep that product "P * V" constant:

So the pressure must have gone up to 450 kilopascals.
Answer:
A = 1.54 x 10⁻⁵ m² = 15.4 mm²
Explanation:
The resistance of a wire can be given by the following formula:

where,
A = smallest cross-sectional area = ?
ρ = resistivity of copper = 1.54 x 10⁻⁸ Ωm
= resistance per unit length of wire = 0.001 Ω/m
Therefore,

<u>A = 1.54 x 10⁻⁵ m² = 15.4 mm²</u>