Answer:
The time it will take for the car to reach a velocity of 28 m/s is 7 seconds
Explanation:
The parameters of the car are;
The acceleration of the car, a = 4 m/s²
The final velocity of the car, v = 28 m/s
The initial velocity of the car, u = 0 m/s (The car starts from rest)
The kinematic equation that can be used for finding (the time) how long it will take for the car to reach a velocity of 28 m/s is given as follows;
v = u + a·t
Where;
v = The final velocity of the car, v = 28 m/s
u = The initial velocity of the car = 0 m/s
a = The acceleration of the car = 4 m/s²
t = =The time it will take for the car to reach a velocity of 28 m/s
Therefore, we get;
t = (v - u)/a
t = (28 m/s - 0 m/s)/(4 m/s²) = 7 s
The time it will take for the car to reach a velocity of 28 m/s, t = 7 seconds.
To solve this problem we will apply the concepts related to the kinematic equations of linear motion. We will calculate the initial velocity of the object, and from it, we will calculate the final position. With the considerations made in the statement we will obtain the total height. Initial velocity of the acorn,
![u = 0m/s](https://tex.z-dn.net/?f=u%20%3D%200m%2Fs)
Also, it is given that the acorn takes 0.201s to pass the length of the meter stick.
![s = ut+\frac{1}{2} at^2](https://tex.z-dn.net/?f=s%20%3D%20ut%2B%5Cfrac%7B1%7D%7B2%7D%20at%5E2)
Replacing,
![1 = u(0.141)+ \frac{1}{2} (9.8)(0.141)^2](https://tex.z-dn.net/?f=1%20%3D%20u%280.141%29%2B%20%5Cfrac%7B1%7D%7B2%7D%20%289.8%29%280.141%29%5E2)
![u =6.4013m/s](https://tex.z-dn.net/?f=u%20%3D6.4013m%2Fs)
The height of the acorn above the meter stick can be calculated as,
![v^2 = u^2 +2gh](https://tex.z-dn.net/?f=v%5E2%20%3D%20u%5E2%20%2B2gh)
![h = \frac{v^2-u^2}{2g}](https://tex.z-dn.net/?f=h%20%3D%20%5Cfrac%7Bv%5E2-u%5E2%7D%7B2g%7D)
![h = \frac{6.4013^2-0^2}{2(9.8)}](https://tex.z-dn.net/?f=h%20%3D%20%5Cfrac%7B6.4013%5E2-0%5E2%7D%7B2%289.8%29%7D)
![h = 2.0906m](https://tex.z-dn.net/?f=h%20%3D%202.0906m)
Also the top of the meter stick is 1.87m above the ground hence the height of the acorn above the ground is
![h = 2.0906+1.87](https://tex.z-dn.net/?f=h%20%3D%202.0906%2B1.87)
![h = 3.9606m](https://tex.z-dn.net/?f=h%20%3D%203.9606m)
A. All living things and objects