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3 years ago

A car is traveling at 70 km/h. It then uniformly decelerates to a complete stop in 12 s. Find its acceleration ( in m/s2 ).

Physics

2 answers:

Lera25 [3.4K]3 years ago

8 0

Answer:

- 1.62 m/s²

Explanation:

initial velocity, u = 70 km/h = 19.44 m/s

time, t = 12 s

final velocity, v = 0

Acceleration is defined by the rate of change of velocity.

By use of first equation of motion

v = u + a t

where, a be the acceleration

0 = 19.44 + a x 12

a = - 1.62 m/s²

Thus, the acceleration is - 1.62 m/s².

Yakvenalex [24]3 years ago

5 0

Answer:

Acceleration will be $-1.620m/sec^2$

Explanation:

We have given initial speed of the car is 70 km/hr

We know that 1 km = 1000 m

And 1 hour = 3600 sec

So $70km/hr=70\times \frac{1000m}{3600sec}=19.444m/sec$

It is given that car stops in 12 sec

So final speed of the car v = 0 m/sec

Time t = 12 sec

From first equation of motion v = u+at

So $0=19.444+a\times 12$

$a=\frac{-19.444}{12}=-1.620m/sec^2$ ( negative sign indicates that speed of the car will constantly decrease )

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3 years ago

An electron and a proton are each placed at rest in an electric field of 500 N/C. Calculate the speed (and indicate the directio

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Answer:

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For electron: 4752000 m/s In the opposite direction of electric field.

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E = 500 N/C, t = 54 ns = 54 x 10^-9 s,

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ae = (1.6 x 10^-19 x 500) / (9.1 x 10^-31) = 8.8 x 10^13 m/s^2

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u = 0, ap = 4.8 x 10^10 m/s^2, t = 54 x 10^-9 s

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3 years ago

Two sealed 1 l containers full of gas are at room temperature. Container a has a pressure of 4 atm and container b has a pressur

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Answer:

The number density of the gas in container A is twice the number density of the gas in container B.

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n = P·V/(RT)

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n₁ = P₁V₁/(RT₁)

n₂ = P₂V₂/(RT₂)

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n₁ = 4V₁/(RT₁)

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3 years ago

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Answer:

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