Heat engines are less than 100% efficient because absolute zero cannot be reached
Answer:![3.874 m/s^2](https://tex.z-dn.net/?f=3.874%20m%2Fs%5E2)
Explanation:
Given
Car speed decreases at a constant rate from 64 mi/h to 30 mi/h
in 3 sec
![60mi/h \approx 26.8224m/s](https://tex.z-dn.net/?f=60mi%2Fh%20%5Capprox%2026.8224m%2Fs)
![34mi/h \approx 15.1994 m/s](https://tex.z-dn.net/?f=34mi%2Fh%20%5Capprox%2015.1994%20m%2Fs)
we know acceleration is given by ![=\frac{velocity}{Time}](https://tex.z-dn.net/?f=%3D%5Cfrac%7Bvelocity%7D%7BTime%7D)
![a=\frac{15.1994-26.8224}{3}](https://tex.z-dn.net/?f=a%3D%5Cfrac%7B15.1994-26.8224%7D%7B3%7D)
![a=-3.874 m/s^2](https://tex.z-dn.net/?f=a%3D-3.874%20m%2Fs%5E2)
negative indicates that it is stopping the car
Distance traveled
![v^2-u^2=2as](https://tex.z-dn.net/?f=v%5E2-u%5E2%3D2as)
![\left ( 15.1994\right )^2-\left ( 26.8224\right )^2=2\left ( -3.874\right )s](https://tex.z-dn.net/?f=%5Cleft%20%28%2015.1994%5Cright%20%29%5E2-%5Cleft%20%28%2026.8224%5Cright%20%29%5E2%3D2%5Cleft%20%28%20-3.874%5Cright%20%29s)
![s=\frac{488.419}{2\times 3.874}](https://tex.z-dn.net/?f=s%3D%5Cfrac%7B488.419%7D%7B2%5Ctimes%203.874%7D)
s=63.038 m
Answer:
20 m/s
30 m/s
Explanation:
Given:
v₀ = -10 m/s
a = -9.8 m/s²
When t = 1 s:
v = v₀ + at
v = (-10 m/s) + (-9.8 m/s²) (1 s)
v = -19.8 m/s
When t = 2 s:
v = v₀ + at
v = (-10 m/s) + (-9.8 m/s²) (2 s)
v = -29.6 m/s
Rounded to one significant figures, the speed of the ball at 1 s and 2 s is 20 m/s and 30 m/s, respectively.
Answer: 18000 coulombs
Explanation:
Given that:
Current, I = 5.0A
Electric charge Q = ?
Time, T = 1 hour
(The SI unit of time is seconds. So, covert 1.0 hour to seconds)
If 1 hour = 60 minutes and 60 seconds = 1 minute
Then, 1.0 hour = (60 x 60)
= 3600 seconds
Since electric charge, Q = current x time
i.e Q = I x T
Q = 5.0 A x 3600 seconds
Q = 18000 coulombs
Thus, 18000 coulombs of charge flows through the lamp in this time.