The final velocity is +15.0 m/s
Explanation:
The motion of the cart is a uniformly accelerated motion (=at constant acceleration), therefore we can use the following suvat equation:

where
v is the velocity at time t
u is the initial velocity
a is the acceleration
t is the time
For the cart in this problem, we have:
u = +3.0 m/s (initial velocity)
(acceleration)
t = 8.0 s (time)
Substituting, we find the final velocity:

Learn more about accelerated motion:
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Answer:
a = 2.22 [m/s^2]
Explanation:
First we have to convert from kilometers per hour to meters per second
![40 [\frac{km}{h}]*[\frac{1h}{3600s}]*[\frac{1000m}{1km}] = 11.11 [m/s]](https://tex.z-dn.net/?f=40%20%5B%5Cfrac%7Bkm%7D%7Bh%7D%5D%2A%5B%5Cfrac%7B1h%7D%7B3600s%7D%5D%2A%5B%5Cfrac%7B1000m%7D%7B1km%7D%5D%20%3D%2011.11%20%5Bm%2Fs%5D)
We have to use the following kinematics equation:

where:
Vf = final velocity = 11.11 [m/s]
Vi = initial velocity = 0
a = acceleration [m/s^2]
t = time = 5 [s]
The initial speed is taken as zero, as the car starts from zero.
11.11 = 0 + (a*5)
a = 2.22 [m/s^2]
By definition, the density of an object is given by:

Where,
M: mass of the object
V: volume of the object
Since the mass and volume of an object are numerical values greater than zero, then it follows that:

It is important to respect the units of each measure.
For this case we can use the grams for the mass and cubic centimeters for the volume.
Answer:
A possible value for density is given by:

Answer:
Explanation:
This question pertains to resonance in air column. It is the case of closed air column in which fundamental note is formed at a length which is as follows
l = λ / 4 where l is length of tube and λ is wave length.
here l = .26 m
λ = .26 x 4 = 1.04 m
frequency of sound = 330 Hz
velocity of sound = frequency x wave length
= 330 x 1.04
= 343.2 m /s
b )
Next overtone will be produced at 3 times the length
so next length of air column = 3 x 26
= 78 cm
c )
If frequency of sound = 256 Hz
wavelength = velocity / frequency
= 343.2 / 256
= 1.34 m
= 134 cm
length of air column for resonance
= wavelength / 4
134/4
= 33.5 cm