Answer:
1) No, the car does not travel at constant speed.
2) V = 9 ft/s
3) No, the car does not travel at constant speed.
4) V = 5.9 ft/s
Explanation:
In order to know if the car is traveling at constant speed we need to derive the given formula. That way we get speed as a function of time:
V(t) = 2*t + 2 Since the speed depends on time, the speed is not constant at any time.
For the average speed we evaluate the formula for t=2 and t=5:
d(2) = 8 ft and d(5) = 35 ft
![V_{2-5}=\frac{d(5)-d(2)}{5-2}=9 ft/s](https://tex.z-dn.net/?f=V_%7B2-5%7D%3D%5Cfrac%7Bd%285%29-d%282%29%7D%7B5-2%7D%3D9%20ft%2Fs)
Again, for the average speed we evaluate the formula for t=1.8 and t=2.1:
d(1.8) = 6.84 ft and d(2.1) = 8.61 ft
![V_{1.8-2.1}=\frac{d(2.1)-d(1.8)}{2.1-1.8}=5.9 ft/s](https://tex.z-dn.net/?f=V_%7B1.8-2.1%7D%3D%5Cfrac%7Bd%282.1%29-d%281.8%29%7D%7B2.1-1.8%7D%3D5.9%20ft%2Fs)
A surface wave is a wave in which particles of the medium undergo a circular motion.
Answer:
![\huge\boxed{\sf Work\ done = 4 kJ}](https://tex.z-dn.net/?f=%5Chuge%5Cboxed%7B%5Csf%20Work%5C%20done%20%3D%204%20kJ%7D)
Explanation:
Since work done is in the form of potential energy, we will use the formula of potential energy here.
We know that,
<h3>P.E. = mgh </h3>
Where,
m = mass = 20 kg
g = acceleration due to gravity = 10 m/s²
h = vertical height = 20 m
So,
<h3>Work done = mgh</h3>
Work done = (20)(10)(20)
Work done = 4000 joules
Work done = 4 kJ
![\rule[225]{225}{2}](https://tex.z-dn.net/?f=%5Crule%5B225%5D%7B225%7D%7B2%7D)
The best thermal conductor is b. metal