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3 years ago

Un tren va a una velocidad de 18m/s frena y se detiene en 15s calcula su aceleracion y la distancia recorrida al frenar

Physics

1 answer:

Rudiy273 years ago

3 0

Answer:

Acceleration is -1.2 m/s² and distance covered is 135 m.

Explanation:

A train going at a speed of 18m / s brakes and stops in 15s calculates its acceleration and the distance traveled when braking

Given that,

The initial speed of the train, u = 18 m/s

Final speed, v = 0

Time, t = 15 s

We need to find acceleration and distance traveled when braking. Let a is acceleration and distance traveled.

Acceleration,

$a=\dfrac{v-u}{t}\\\\a=\dfrac{0-18}{15}\\\\a=-1.2\ m/s^2$

Using third equation of motion,

$v^2-u^2=2ad\\\\d=\dfrac{v^2-u^2}{2a}\\\\d=\dfrac{0^2-18^2}{2\times (-1.2)}\\\\d=135\ m$

Hence, acceleration is -1.2 m/s² and distance covered is 135 m.

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A 52 kg child on a swing is travelling at 6 m/s . What is his gravitational potential energy if he has 1000 J of the mechanical

DiKsa [7]

Answer:

The correct answer is "64 J".

Explanation:

The given values are:

Mass,

m = 52 kg

Velocity,

v = 6 m/s

Mechanical energy,

= 1000 J

Now,

The gravitational potential energy will be:

⇒ $P.E=1000-\frac{1}{2}mv^2$

$=1000-\frac{1}{2}\times 52\times (6)^2$

$=1000-26\times 36$

$=1000-936$

$=64 \ J$

7 0

2 years ago

Helllppp mee!

Fed [463]

Given:

m = 0.14 kg

v = 18 m/s

To find:

Kinetic energy= ?

Explanation:

Kinetic energy of the object is possessed when the object is in motion. It is define as the work done required to accelerate a body from rest to motion. Unit of energy is Joule and it is same as unit of work done. Energy is nothing but the capacity to do work.

Solution:

Kinetic energy of the ball is given by,

Kinetic energy = $\frac{1}{2}m v^{2}$