Answer:
T = 0.225 s
Explanation:
The speed of a projectile at the highest point of its motion is the horizontal speed of the projectile. Considering the horizontal motion with negligible air resistance, we can use the following formula:

where,
T = Total time of ball in air = ?
R = Horizontal distance covered = 40 m
= horizontal speed = 9 m/s
Therefore,

<u>T = 0.225 s</u>
Answer:
when you tell someone over and over to stop bothering you and they dont so i think you should tell a teacher
Explanation:
Answer:
The current is halved
Explanation:
The relationship between the current and the resistance is given by Ohm's Law, as follows:

where,
V = Voltage
I = Current
R = Resistance
Therefore, if we double the resistance:

Hence the correct option is:
<u>The current is halved</u>
Answer:
Friction is useful in some cases like walking and cycling ..
but it is unwanted in machines as it create unwanted sounds and heat .,due to which we loss energy
Explanation:
mark me as brainliest ❤️
Answer:Reflection
Explanation:
The throwing back of a sound wave without absorbing it is called reflection
In acoustic reflection of sound is termed as echo i.e. sound arrived at the listener after a particular delay depending upon the position of barrier to the observer.
The reflection of sound is used in many devices like megaphone, trumpets, etc. It is also used in auditorium such that the ceiling of the auditorium is curved for multiple reflections of sound so that sound can be reached at every corner of the auditorium.