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andrezito [222]
1 year ago
8

A 20kg mass approaches a spring at a speed of 30 m/s. The mass compresses the spring 12cm before coming to a stop. Calculate the

spring constant k of the spring (N/m). A. 150 kN/m B. 41.7 kN/m C. 125 N/m D. 1.25 MN/m
Physics
1 answer:
Oksana_A [137]1 year ago
5 0

Answer:

625000 N/ m

Explanation:

m= 20 kg

v= 30 m/s

x= 12 cm

k = ?

Here when the mass when hits at spring its speed is

Vi= 30 m/s

Finally it comes to rest after compressing for 12 cm

i-e Vf = 0 m/s

Distance= S= 12 cm = 0.12 m

using

2aS= Vf2 - Vi2

==> 2a ×0.12 = o- 30 × 30

==> a = 900 ÷ 0.24 = 3750 m/sec2

Now we know;

F = ma

F= -Kx

==> ma= -kx

==> 20 × 3750 = -K × 0.12

==> k = 625000 N/ m

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On an amusement park ride, passengers are seated in a horizontal circle of radius 7.5 m. The seats begin from rest and are unifo
timofeeve [1]

Answer:

a = 0.5 m/s²

Explanation:

Applying the definition of angular acceleration, as the rate of change of the angular acceleration, and as the seats begin from rest, we can get the value of the angular acceleration, as follows:

ωf = ω₀ + α*t

⇒ ωf = α*t ⇒ α = \frac{wf}{t} = \frac{1.4 rad/s}{21 s} = 0.067 rad/s2

The angular velocity, and the linear speed, are related by the following expression:

v = ω*r

Applying the definition of linear acceleration (tangential acceleration in this case) and angular acceleration, we can find a similar relationship between the tangential and angular acceleration, as follows:

a = α*r⇒ a = 0.067 rad/sec²*7.5 m = 0.5 m/s²

3 0
2 years ago
An ambulance moving at 42 m/s sounds its siren whose frequency is 450 hz. a car is moving in the same direction as the ambulance
Korvikt [17]
(a) Since the ambulance and the car are moving one relative to each other, we have to use the general formula of the Doppler effect, which gives us the shift of the frequency of the siren as heard by an observer in the car:
f'=( \frac{v+v_o}{v+v_s} )f
where
f' is the apparent frequency as heard by the observer in the car
v is the velocity of the wave 
v_o is the velocity of the observer (positive if it is moving towards the source, negative if it is moving away)
v_s is the velocity of the source (positive if the source is moving away from the observer, negative if is is moving towards it)
f is the real frequency of the sound

In the first part of the problem:
v=343 m/s (speed of the sound wave)
v_o =-25 m/s (the car is moving away from the ambulance)
v_s = -42 m/s (the ambulance is moving towards the car)
f=450 Hz (original frequency of the sound)

If we plug the numbers into the formula, we find
f'=( \frac{343 m/s-25 m/s}{343 m/s-42 m/s} )(450 Hz)=475 Hz

b) This time, the ambulance passes the car, so the ambulance is now moving away from the car; this means that v_s must be positive:
v_s=+42 m/s
Moreover, the car is now moving towards the ambulance, so we should reverse also the sign of v_o:
v_o=+25 m/s
All the other data do not change, so if we use the same formula as before, we find
f'=( \frac{343 m/s+25 m/s}{343 m/s+42 m/s} )(450 Hz)=430 Hz
8 0
2 years ago
Nisha was making a list of things that are obtained from plants and Amol was making a list of things that can dissolve in water.
Allisa [31]

Answer:

Sugar

Explanation:

Nisha's list:                               Amol's list

  Jute                                          Vinegar

  Wood                                       Lemon juice

  Rubber                                   Cooking soda

Nisha's list is made up of things that can be derived from plants. From the list given, oil, sugar and cotton can also be obtained from plants.

Most plant materials are organic matter.

Amol's list is made up of things that can dissolve in water. Sugar and table salt can also be dissolved in water.

Water is able to dissolve these materials because they are polar compounds. One rule of solubility is that like dissolves like.

New list:

Nisha's list:                               Amol's list

  Jute                                          Vinegar

  Wood                                       Lemon juice

  Rubber                                   Cooking soda

  Sugar                                       Sugar

                                   

Only sugar from the list can be added to both lists. It can be obtained from plant and can also dissolve in water.

                                             

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2 years ago
What conclusion can be derived by comparing the central tendencies of the two data sets?
zhannawk [14.2K]
The answer is B. I don’t think I need to explain this,
Mean is average, Mode is the most common number, and Median is the middle number when you put the numbers is numerical order from least to greatest
3 0
2 years ago
The diagram shows Ned’s movement as he left his house and traveled to different places throughout the day. Which reference point
aleksley [76]

The pet store would be the reference point because it is where he started and it will not move. Hope this helped.

6 0
2 years ago
Read 2 more answers
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