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Alona [7]
3 years ago
5

A train travelling at 20m/s undergoes a uniform deceleration of 2m/s2 when brakes are applied.. calculate the time taken to come

to rest and distance travel from the place where the brakes were applied ​
Physics
1 answer:
VLD [36.1K]3 years ago
6 0

Answer:

a) 10 seconds

b) 100 meters

Explanation:

<u>Accelerated Motion </u>

If an object is moving at contant speed, we know it has zero net force applied. As soon as an unbalanced force appears, the object accelerates (positive or negative) depending on the direction of the force with respect to movement. The speed of an object subject to acceleration is given by

v_f=v_o+at

The distance traveled is given by

\displaystyle x=v_ot+\frac{at^2}{2}

a)

Our train is travelling at 20m/s when it decelerates at -2\ m/s^2 (negative for it's against movement). If nothing else happens, it will eventually stop (v_f=0). We can compute the time at which it happens :

\displaystyle t=\frac{v_f-v_o}{a}

Knowing\ v_f=0

\displaystyle t=\frac{-20}{-2}=10\ sec

b)

The distance traveled is

\displaystyle x=v_ot+\frac{at^2}{2}

\displaystyle x=(20)(10)-\frac{2(10)^2}{2}

\displaystyle x=100\ m

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Lorico [155]

Answer:

See below

Explanation:

<u>I will use   3 x 10^8 m/s for speed or wave</u>

speed = wavelength * frequency

3 x 10^8  = w * 7.34 x 10^2     <====== are you sure this isn't KILO Hz ?

w = <u>408719. 3 meters   </u>

4 0
2 years ago
______ creates heat in earths interior when dense substance sink into earths core.
anastassius [24]

The answer is A. Friction

hope this helps :)

7 0
3 years ago
IF U ANSWER I WILL MARK U BRAINLLIEST
goldfiish [28.3K]

Explanation:

a) Density is the amount of mass in a specific amount of volume

b) Some substances are less dense than water so will float and vice versa

c) The wooden plank has less density than water due to having larger volume and vice versa with the wooden block since volume and density are inversely proportional

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6 0
3 years ago
Read 2 more answers
A body of mass 5.0 kg is suspended by a spring which stretches 10 cm when the mass is attached. It is then displaced downward an
Dominik [7]

Answer:

position as a function of time is y = 0.05 × cos(9.9)t

Explanation:

given data

mass = 5 kg

length = 10 cm = 0.1 m

displaced = 5 cm

to find out

position as a function of time

solution

we will apply here equilibrium that is

mass × g = k × length

put here value and find k

k = \frac{5*9.8}{.01}

k = 490 N/m

and ω is

ω = \sqrt{\frac{k}{m} }

ω = \sqrt{\frac{490}{5} }

ω = 9.9

so here position w.r.t  time is

y = 0.05 × cosωt

y = 0.05 × cos(9.9)t

so position as a function of time is y = 0.05 × cos(9.9)t

8 0
3 years ago
a sound has a frequency of 230 hz. what is the velocity of this sound if it has a wavelength of 46 cm?​
lapo4ka [179]

Answer:

V=f×λ

Where,

V is the velocity of the wave measure using m/s.

f is the frequency of the wave measured using Hz.

λ is the wavelength of the wave measured using m.

transform 46 cm in m = 0.46m and there u have it

Explanation:

6 0
2 years ago
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