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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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saveliy_v [14]

The static friction exerted on the block by the incline is \mu _ s _1 Mgcos \ \theta.

The given parameters;

  • <em>mass of the block, = M</em>
  • <em>coefficient of static friction in section 1, = </em>\mu_s_1<em />
  • <em>angle of inclination of the plane, = θ</em>

<em />

The normal force on the block is calculated as follows;

Fₙ = Mgcosθ

The static friction exerted on the block by the incline is calculated as follows;

F_s = \mu_s F_n\\\\F_s = \mu _s_1(Mg cos\ \theta)\\\\F_s = \mu _s_1 Mgcos\ \theta

Thus, the static friction exerted on the block by the incline is \mu _ s _1 Mgcos \ \theta

Learn more here:brainly.com/question/17237604

3 0
3 years ago
If you start rolling down this hill, your potential energy will be converted to kinetic energy. At the bottom of the hill ypu KE
Serjik [45]

Answer:

v=\sqrt{(2x/m)}\  \ m/s

Explanation:

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Let x be the value of Kinetic Energy.

We know that

PE=KE=x\\x=\frac{1}{2}mv^2\\

Make v the subject of the formula to get speed at the bottom of the hill.

v^2=2x/m\\v=\sqrt{2x/m}

8 0
3 years ago
Example to measure the interval of time of a small stone dropped from 1m height.
Shalnov [3]

Answer:

The time required is 0.45 s.

Explanation:

Height, h = 1 m

initial velocity, u = m/s

Let the time is t.

Use second equation of motion

h = u t + 0.5 at^2\\\\1 = 0 +0.5 \times 9.8 \times t^2\\\\t = 0.45 s

7 0
3 years ago
In a US household, the voltage in an electric outlet (in volts) is given by the following equation, where t is in seconds. V = 1
Damm [24]

Answer:

a) The voltage in an european house is 2,17 times greater than in an american House. That is 183 volts more than in US.

b) the number of cycles or oscillations for an US House is 60 cycles per second

Explanation:

To answer this this question you have to know the wave equation:

x(t) = A Sin (a + b.t)

where

x(t) = is the position as a time function... In this exercise we could call V(t) instead of x(t) beacause we want to know voltage vs time.

A = is the amplitude of the wave. In this case the maximum voltage that can be reached.

a = is the offset in time or number of waves (zero in this exercise)

b =  constant that varies the frequency

then...

a) calculate the ratio between both amplitudes:

A_{Europe} / A_{US} = 339 / 156 = 2,17

b) frequency (Oscillations) is:

b = 2pi/T = 2pi*F    remember that: T = 1/F

where

F = frequency

T = Period

so for US household we have:

120pi =2pi*F

therefore

F = 120/2 = 60 Hertz

5 0
4 years ago
What is the definition of Physics?​
pychu [463]

Answer:

This is the simplified definition.

Explanation:

The main goal of physics is to explain how things move in space and time and understand how the universe behaves.

4 0
4 years ago
Read 2 more answers
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