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3 years ago

How can gravitational energy play an important part of my life

Physics

1 answer:

m_a_m_a [10]3 years ago

8 0

Answer:

Explanation:

Well, lets say you park your car on the top of a hill, gravitational energy prevents it from the car falling back. Or a snow pack, aka before a potential avalanche. Though gravity cannot keep it safe forever, gravitational energy keeps it from crashing asap. In this case, it gives you time to escape. Altogether, gravitational force keeps the earth in it's atmosphere.

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A 2.0 kg pendulum has an initial total energy of 20 J. Calculate the energy lost as heat if the pendulum is 0.10 m high and is t

Maurinko [17]

The correct answer is (A) 2.0 J

Total energy of the pendulum is the sum of its kinetic and potential energy. At the instant of time, when the pendulum is at a height h and has a speed v, Its energy is given by,

$E=mgh+\frac{1}{2} mv^2$

Substitute 2.0 kg for m, the mass of the pendulum, 9.81 m/s² for g, the acceleration due to gravity, 0.10 m for h and 4.0 m/s for v.

$E=mgh+\frac{1}{2} mv^2\\ =(2.0kg)(9.81m/s^2)(0.10 m)+\frac{1}{2}(2.0kg)(4.0m/s)^2\\ =17.962J$

The pendulum has an initial energy of 20 J. the energy lost is given by,

$\Delta E=(20J)-(17.962J)\\ =2.038J=2.0J$

Thus, the energy lost by the pendulum is (A) 2.0 J

4 0

3 years ago

The barricade at the end of a subway line has a large spring designed to compress 2.00 m when stopping a 1.10 ✕ 105 kg train mov

Mrac [35]

Answer:

(a) k = 1684.38 N/m = 1.684 KN/m

(b) Vi = 0.105 m/s

Explanation:

(a)

First, we find the deceleration of the car. For that purpose we use 3rd equation of motion:

2as = Vf² - Vi²

a = (Vf² - Vi²)/2s

where,

a = deceleration = ?

Vf = final velocity = 0 m/s (since, train finally stops)

Vi = Initial Velocity = 0.35 m/s

s = distance covered by train before stopping = 2 m

Therefore,

a = [(0 m/s)² - (0.35 m/s)²]/(2)(2 m)

a = 0.0306 m/s²

Now, we calculate the force applied on spring by train:

F = ma

F = (1.1 x 10⁵ kg)(0.0306 m/s²)

F = 3368.75 N

Now, for force constant, we use Hooke's Law:

F = kΔx

where,

k = Force Constant = ?

Δx = Compression = 2 m

Therefore.

3368.75 N = k(2 m)

k = (3368.75 N)/(2 m)

k = 1684.38 N/m = 1.684 KN/m

(c)

Applying Hooke's Law with:

Δx = 0.6 m

F = (1684.38 N/m)(0.6 m)

F = 1010.62 N = 1.01 KN

(b)

Now, the acceleration required for this force is:

F = ma

1010.62 N = (1.1 kg)a

a = 1010.62 N/1.1 x 10⁵ kg

a = 0.0092 m/s²

Now, we find initial velocity of train by using 3rd equation of motion:

2as = Vf² - Vi²

a = (Vf² - Vi²)/2s

where,

a = deceleration = -0.0092 m/s² (negative sign due to deceleration)

Vf = final velocity = 0 m/s (since, train finally stops)

Vi = Initial Velocity = ?

s = distance covered by train before stopping = 0.6 m

Therefore,

-0.0092 m/s² = [(0 m/s)² - Vi²]/(2)(0.6 m)

Vi = √(0.0092 m/s²)(1.2 m)

Vi = 0.105 m/s

4 0

3 years ago

When does sound become damaging to the human ear?

Vlad1618 [11]

When someone yells in it

5 0

2 years ago

What will be the weight (acceleration due to gravity on the moon is 1/6 that of the earth

jeyben [28]

Answer:

The weight will be 1/6 of whatever it is on Earth.

Explanation:

Remember F=ma

If the acceleration decreases by a factor of 6 while the mass stays constant, you can see the force (the weight) will also decrease by the same factor.

7 0

3 years ago

A dog runs 50 meters north 40 meters east and 20 meters south what is the displacement

Allisa [31]

So....
imagine the x and y axis or draw it on a piece of paper, a white board or even on your wall if you like. I'm kidding just draw it on a piece of paper

50m up and 20m down
the dog's displacement is 50 - 20 which is 30
your answer is 30m north

3 0

3 years ago