Answer:

Explanation:
Given:
height above the horizontal form where the ball is hit, 
angle of projectile above the horizontal, 
initial speed of the projectile, 
<u>Firstly we find the </u><u>vertical component of the initial velocity</u><u>:</u>



During the course of ascend in height of the ball when it reaches the maximum height then its vertical component of the velocity becomes zero.
So final vertical velocity during the course of ascend:
Using eq. of motion:
(-ve sign means that the direction of velocity is opposite to the direction of acceleration)

(from the height where it is thrown)
<u>Now we find the time taken to ascend to this height:</u>



<u>Time taken to descent the total height:</u>
- we've total height,


- during the course of descend its initial vertical velocity is zero because it is at the top height, so



<u>Now the total time taken by the ball to hit the ground:</u>



42) The sailboat travels east with velocity

, while the current moves south with speed

. Since the two velocities are perpendicular to each other, he resultant velocity will be given by the Pytagorean theorem:

and the direction is in between the two original directions, therefore south-east. So, the correct answer is
D) 42 mph southeast
43) Since the light moves by uniform motion, we can calculate the distance corresponding to one light year by using the basic relationship between velocity, space and time. In fact, we know the velocity:

and the time is one year, corresponding to:

therefore, the distance corresponding to one light year is:

Therefore, the correct answer is D.
44) For the purpose of the problem, we can assume that the light travels instantaneously from the flash to us (because the distances involved are very small), so the time between the flash and the thunder corresponds to the time it took for the sound to travel to us.
The speed of sound is

And since the time between the flash and the thunder is t=3 s, the distance is

Therefore, the correct answer is A) 3/5 mile.
The frequency of the radio waves from the fm station is:

And the speed of the waves corresponds to the speed of light:

Therefore, the wavelength of the radio waves can be found by using the following equation:
This question involves the concepts of the law of conservation of energy and kinetic energy.
The girl's fastest speed is "3.7 m/s".
According to the law of conservation of energy, the girl will have the fastest speed at mean position, which will be calculated as follows:
Loss in Potential Energy = Gain in Kinetic Energy

where,
v = maximum speed = ?
g = acceleration due to gravity = 9.81 m/s²
Δh = change in height = 1.3 m - 0.6 m = 0.7 m
Therefore,

<u>v = 3.7 m/s</u>
<u></u>
Learn more about the Law of Conservation of Energy here:
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