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3 years ago

a bus accelerates at -0.5 m/s^2 for 12.5 seconds if the bus had an initial speed of 31 /s what is its new speed

Physics

2 answers:

Arlecino [84]3 years ago

8 0

Answer:

as the other person said, the answer is 24.75 m/s

Explanation:

aleksandr82 [10.1K]3 years ago

3 0

Vf=v0+at so 31m/s-.5m/s^2*12.5= 24.75m/s is the new speed. the negative sign is showing a deceleration.

Hope this helps! Please rate if you like my answer! Thank you!!

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Menghitung jisim molekul relatif dan jisim formula relatif

kumpel [21]

Answer:

oh def good it's qiqiowwwjwjjwjwjjs is jsjwjiq is wiiwjwjsje

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3 years ago

An object of 4 cm length is placed at a distance of 18 cm in front of a convex mirror of radius of curvature 30 cm. Find the pos

erica [24]

Answer:

The position is 8.18cm from the mirror.

Nature is b=virtual

Size is 1.82cm

Explanation:

Note that for a convex mirror, the image distance and the focal length are negative;

Given

Object height H0 = 4cm

object distance u = 18cm

Radius of curvature R = 30cm

Since f = R/2

f = 30/2

f = -15cm

Recall that:

$\frac{1}{f} =\frac{1}{u}+ \frac{1}{v}\\\frac{1}{-15}=\frac{1}{18}+\frac{1}{v} \\\frac{1}{v} =\frac{1}{-15} -\frac{1}{18}\\ \frac{1}{v} = \frac{-18-15}{270}\\\frac{1}{v} = \frac{-33}{270}\\v=\frac{-270}{33}\\v=-8.18cm$

Since the image distance is negative, this shows that the image is a virtual image.

To get the size:

$\frac{H_1}{H_0}=\frac{v}{u}\\\frac{H_1}{4}=\frac{8.18}{18}\\18H_i=32.72\\H_i=\frac{32.72}{18}\\H_i= 1.82cm$

3 0

3 years ago

What frequency is received by a person watching an oncoming ambulance moving at 110 km/h and emitting a steady 800-Hz sound from

Strike441 [17]

To develop this problem we will apply the concepts related to the Doppler effect. The frequency of sound perceive by observer changes from source emitting the sound. The frequency received by observer $f_{obs}$ is more than the frequency emitted by the source. The expression to find the frequency received by the person is,

$f_{obs} = f_s (\frac{v_w}{v_w-v_s})$

$f_s$ = Frequency of the source

$v_w$ = Speed of sound

$v_s$ = Speed of source

The velocity of the ambulance is

$v_s = 119km/h (\frac{1000m}{1km})(\frac{1h}{3600s})$

$v_s = 30.55m/s$

Replacing at the expression to frequency of observer we have,

$f_{obs} = 800Hz(\frac{345m/s}{345m/s-30.55m/s})$

$f_{obs} = 878Hz$

Therefore the frequency receive by observer is 878Hz

8 0

3 years ago

A vector has a magnitude of 30m at an angle of 225 degrees with respect to the positive x-axis and has a magnitude of 13m.what a

Aneli [31]

Answer:

I'm pretty sure this is not a complete question. My guess is that you are trying to add/subtract vectors. Vectors have both magnitude and direction, so vector A is pretty clear, but a magnitude of 13 (i'm guessing a resultant) without a direction is weird.

IF 13 is the magnitude of the resultant, vector B added to vector A could have any magnitude 17 ≤ B ≤ 43

It could have any direction of

θ = (225 - 180) ± arcsin(13/30)

θ = 45 ± 25.679...

70.679 ≤ θ ≤ 19.321

components of vector B would be

Bx = |B|cosθ

By = |B|sinθ

3 0

2 years ago

A sled slides down a hill with friction between the sled and hill but negligible alr resistance. Which of the following must be

Andreyy89

Answer:

A) The sum of the kinetic energy and the gravitational potential energy changes by an amount equal to the energy dissipated by friction,

Explanation:

The kinetic energy is the energy that the object has and is defied by the work that is needed to accelerate the body.

The gravitational potential is a mechanism by which an equal amount of energy is being transferred per unit mass that is needed for the object to move from the specific location.

Hence when the sled moves down the hill with the force of gravity it has negligible resistance as an equal amount of energy is dissipated.

8 0

3 years ago