Answer:
The velocities of each ball are
![v_{f2}=8.08 m/s](https://tex.z-dn.net/?f=v_%7Bf2%7D%3D8.08%20m%2Fs)
![v_{f1}=5.28 m/s](https://tex.z-dn.net/?f=v_%7Bf1%7D%3D5.28%20m%2Fs)
Explanation:
Using the conservation of momentum to find the velocity of each balls after the collision
![m_1*v_1+m_2*v_2=m_1*v_{f1}+m_2*v_{f2}](https://tex.z-dn.net/?f=m_1%2Av_1%2Bm_2%2Av_2%3Dm_1%2Av_%7Bf1%7D%2Bm_2%2Av_%7Bf2%7D)
![3kg*8m/s+2kg*4m/s=3kg*v_{f1}+2kg*v_{f2}](https://tex.z-dn.net/?f=3kg%2A8m%2Fs%2B2kg%2A4m%2Fs%3D3kg%2Av_%7Bf1%7D%2B2kg%2Av_%7Bf2%7D)
![32 kg*m/s=3kg*v_{f1}+2kg*v_{f2}](https://tex.z-dn.net/?f=32%20kg%2Am%2Fs%3D3kg%2Av_%7Bf1%7D%2B2kg%2Av_%7Bf2%7D)
Here have one equation but have two variable don't know so
![e=\frac{v_{f2}-v_{f1}}{v_1-v_2}](https://tex.z-dn.net/?f=e%3D%5Cfrac%7Bv_%7Bf2%7D-v_%7Bf1%7D%7D%7Bv_1-v_2%7D)
![0.7=\frac{v_{f2}-v_{f1}}{8m/s-4m/s}](https://tex.z-dn.net/?f=0.7%3D%5Cfrac%7Bv_%7Bf2%7D-v_%7Bf1%7D%7D%7B8m%2Fs-4m%2Fs%7D)
![v_{f2}-v_{f1}=2.8](https://tex.z-dn.net/?f=v_%7Bf2%7D-v_%7Bf1%7D%3D2.8)
Now have two equations and two variables so solving using
![v_{f2}=8.08 m/s](https://tex.z-dn.net/?f=v_%7Bf2%7D%3D8.08%20m%2Fs)
![v_{f1}=5.28 m/s](https://tex.z-dn.net/?f=v_%7Bf1%7D%3D5.28%20m%2Fs)
Answer:
<em>a) 3.6 ft</em>
<em>b) 12.4 ft</em>
Explanation:
Distance between mirrors = 6.2 ft
difference from from the mirror you face = 1.8 ft
a) you stand 1.8 ft in front of the mirror you face.
According to plane mirror rules, the image formed is the same distance inside the mirror surface as the distance of the object (you) from the mirror surface. From this,
your distance from your first "front" image = 1.8 ft + 1.8 ft = <em>3.6 ft</em>
b) The mirror behind you is 6.2 - 1.8 = 4.4 ft behind you.
the back mirror will be reflected 3.6 + 4.4 = 8 ft into the front mirror,
the first image of your back will be 4.4 ft into the back mirror,
therefore your distance from your first "back" image = 8 + 4.4 = <em>12.4 ft</em>
Answer:
216 m
Explanation:
Assuming a straight line:
Δx = vt
Δx = (12 m/s) (18 s)
Δx = 216 m
Answer:
v ’= 21.44 m / s
Explanation:
This is a doppler effect exercise that changes the frequency of the sound due to the relative movement of the source and the observer, the expression that describes the phenomenon for body approaching s
f ’= f (v + v₀) / (v-
)
where it goes is the speed of sound 343 m / s, v_{s} the speed of the source v or the speed of the observer
in this exercise both the source and the observer are moving, we will assume that both have the same speed,
v₀ = v_{s} = v ’
we substitute
f ’= f (v + v’) / (v - v ’)
f ’/ f (v-v’) = v + v ’
v (f ’/ f -1) = v’ (1 + f ’/ f)
v ’= (f’ / f-1) / (1 + f ’/ f) v
v ’= (f’-f) / (f + f’) v
let's calculate
v ’= (3400 -3000) / (3000 +3400) 343
v ’= 400/6400 343
v ’= 21.44 m / s
Force = mass * acceleration
acceleration = change_in_velocity / time
so:
force = 740 kg * (19 m/s - 0 m/s) / 2.0 s
= 740 * 19 / 2 kg m per second^{2}
= 7030 kg m per second^{2}
= 7030 newtons of force