Answer:
Velocity = 4.33[m/s]
Explanation:
The total energy or mechanical energy is the sum of the potential energy plus the kinetic energy, as it is known the velocity and the height, we can determine the total energy.
![E_{M}=E_{p} + E_{k} \\E_{p} = potential energy [J]\\E_{k} = kinetic energy [J]\\where:\\E_{p} =m*g*h\\E_{p} = 4*9.81*0.5=19.62[J]\\E_{k}=\frac{1}{2} *m*v^{2} \\E_{k}=\frac{1}{2} *4*(3)^{2} \\E_{k}=18[J]\\Therefore\\E_{M} =18+19.62\\E_{M}=37.62[J]](https://tex.z-dn.net/?f=E_%7BM%7D%3DE_%7Bp%7D%20%20%2B%20E_%7Bk%7D%20%5C%5CE_%7Bp%7D%20%3D%20potential%20energy%20%5BJ%5D%5C%5CE_%7Bk%7D%20%3D%20kinetic%20energy%20%5BJ%5D%5C%5Cwhere%3A%5C%5CE_%7Bp%7D%20%3Dm%2Ag%2Ah%5C%5CE_%7Bp%7D%20%3D%204%2A9.81%2A0.5%3D19.62%5BJ%5D%5C%5CE_%7Bk%7D%3D%5Cfrac%7B1%7D%7B2%7D%20%2Am%2Av%5E%7B2%7D%20%20%5C%5CE_%7Bk%7D%3D%5Cfrac%7B1%7D%7B2%7D%20%2A4%2A%283%29%5E%7B2%7D%20%5C%5CE_%7Bk%7D%3D18%5BJ%5D%5C%5CTherefore%5C%5CE_%7BM%7D%20%3D18%2B19.62%5C%5CE_%7BM%7D%3D37.62%5BJ%5D)
All this energy will become kinetic energy and we can find the velocity.
![37.62=\frac{1}{2} *m*v^{2} \\v=\sqrt{\frac{37.62*2}{4} } \\v=4.33[m/s]](https://tex.z-dn.net/?f=37.62%3D%5Cfrac%7B1%7D%7B2%7D%20%2Am%2Av%5E%7B2%7D%20%5C%5Cv%3D%5Csqrt%7B%5Cfrac%7B37.62%2A2%7D%7B4%7D%20%7D%20%5C%5Cv%3D4.33%5Bm%2Fs%5D)
Answer:
Drug abuse is best defined as the nonmedical or improper use of a drug that can interfere with a healthy life.
For example, a person that is addicted to cocaine will use it everyday, and will develope agressive behavior, anxiety, sleep disorder, paranoia etc.
This person could get addicted at the point of comiting a robbery, killing and much more.
Answer:
588 J
Explanation:
PE (potential energy) = (mass) x (gravity) x (height)
mass = 12 kg
gravity = 9.8m/s^2
height = 5 m
PE = (12) x (9.8) x (5) = 588 J (Joules)
Complete Question
A commuter train passes a passenger platform at a constant speed of 39.6 m/s. The train horn is sounded at its characteristic frequency of 350 Hz.
(a)
What overall change in frequency is detected by a person on the platform as the train moves from approaching to receding
(b) What wavelength is detected by a person on the platform as the train approaches?
Answer:
a

b

Explanation:
From the question we are told that
The speed of the train is 
The frequency of the train horn is 
Generally the speed of sound has a constant values of 
Now according to dopplers equation when the train(source) approaches a person on the platform(observe) then the frequency on the sound observed by the observer can be mathematically represented as

substituting values


Now according to dopplers equation when the train(source) moves away from the person on the platform(observe) then the frequency on the sound observed by the observer can be mathematically represented as

substituting values


The overall change in frequency is detected by a person on the platform as the train moves from approaching to receding is mathematically evaluated as



Generally the wavelength detected by the person as the train approaches is mathematically represented as



Answer:
Explanation:
Plastic or rubber are regarded as an insulator, and an insulator does not allow the flow of electric current through them, so the handles of screwdrivers as well as pliers that electricians use in repairing is been covered with plastic or rubber so that electric current is prevented to pass through it to the body of electricians to avoid been electrocuted as well as shock.