¿Qué distancia en metros recorre una persona en bicicleta, en 15 min, si lleva una velocidad constante de 12 m/s? (10 puntos)

Voltage sources are used to sustain

Sindrei [870]

The movement of electric charge

5 0

3 years ago

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A ball with 100 J of PE is released from a height of 10 m. What will be the KE of the ball at 5

harkovskaia [24]

Answer:

The kinetic energy is: 50[J]

Explanation:

The ball is having a potential energy of 100 [J], therefore

PE = [J]

The elevation is 10 [m], and at this point the ball is having only potential energy, the kinetic energy is zero.

$E_{p} =m*g*h\\where:\\g= gravity[m/s^{2} ]\\m = mass [kg]\\m= \frac{E_{p} }{g*h}\\ m= \frac{100}{9.81*10}\\\\m= 1.01[kg]\\\\$

In the moment when the ball starts to fall, it will lose potential energy and the potential energy will be transforme in kinetic energy.

When the elevation is 5 [m], we have a potential energy of

$P_{e} =m*g*h\\P_{e} =1.01*9.81*5\\\\P_{e} = 50 [J]\\$

This energy is equal to the kinetic energy, therefore

Ke= 50 [J]

8 0

3 years ago

A small pebble and one large boulder start at the same height and begin rolling down the side of a mountain. Which object would

vitfil [10]

Answer:

The small pebble

Explanation:

Since the potential energy, P.E lost equals kinetic energy, K.E gained,

P.E = K.E

P.E = mgh = K.E

So, K.E = mgh where g = acceleration due to gravity and h = height of drop

Since h and g are constant

K.E ∝ m

So, the kinetic energy of the object is directly proportional to its mass. Thus, the object with the smaller mass has the lesser kinetic energy.

Since the object with the smaller mass is the small pebble, so the small pebble would have less kinetic energy as it crashes on the road at the bottom of the mountain.

8 0

3 years ago

What is the charge on an object that has 1.09x10^13 excess electrons?

Nadya [2.5K]

Answer:

$-1.74\cdot 10^{-6} C$

Explanation:

The electron is the particle that rotates around the nucleus of the atom; it has a negative electric charge equal to :

$e=-1.6\cdot 10^{-19}C$

which is known as fundamental charge.

For an object containing N excess electrons, the total charge of the object is

$Q=Ne$

In this problem, the number of excess electrons in the object is:

$N=1.09\cdot 10^{13}$

Therefore, by plugging it the numbers, we can find the value of Q, the total charge of the object:

$Q=(1.09\cdot 10^{13})(-1.6\cdot 10^{-19})=-1.74\cdot 10^{-6} C$

5 0

4 years ago

Please help!!!!!!!!!

aleksandr82 [10.1K]

1. This question asks about velocity, so A and B are not correct. The car's velocity after 15 s with acceleration 2.00 m/s² would be

(2.00 m/s²) (15 s) = 30 m/s

[D]

2. Because Ima is slowing down to a stop, the acceleration is negative. Let x be the displacement of her vehicle during this motion. Then

0² - (30.0 m/s)² = 2 (-8.00 m/s²) x

==> x = (30.0 m/s)²/(2 (8.00 m/s²)) = 56.25 m ≈ 65.3 m

[A]

3. Since acceleration is constant, the average velocity is exactly the average of the initial and final velocities:

(21.0 m/s + 0 m/s)/2 = 10.5 m/s

The average (and thus instantaneous) acceleration during this time is equal to the change in velocity divided by the change in time:

(0 m/s - 21.0 m/s)/(6.00 s) = -3.50 m/s²

If x is the distance traveled as the car comes to a stop, then

0² - (21.0 m/s)² = 2 (-3.50 m/s²) x

==> x = (21.0 m/s)² / (2 (3.50 m/s²)) = 63.0 m

[A]

4.a. Assuming the sprinter's acceleration is constant, the average acceleration would be a such that

(11.5 m/s)² - 0² = 2 a (15.0 m)

==> a = (11.5 m/s)² / (2 (15.0 m)) ≈ 4.41 m/s²

4.b. By definition of average acceleration,

4.41 m/s² = (11.5 m/s - 0 m/s)/t

==> t = (11.5 m/s)/(4.41 m/s²) ≈ 2.61 s

5. At maximum height, any thrown object has zero velocity, so if it was thrown with an initial speed v, at its highest point we have

0² - v ² = 2 (-g) (91.5 m)

==> v = √(2g (91.5 m)) ≈ 42.3 m/s

(where I use g = 9.80 m/s²)

6.a. The brick's velocity after 7.0 s is

-g (7.0 s) = -68.6 m/s ≈ -69 m/s

6.b. The brick is presumably dropped from rest, so it is displaced by x such that

(-68.6 m/s)² - 0² = 2 (-g) x

==> x = -240.1 m ≈ -240 m

which is to say it falls a distance of 240 m. (The displacement is negative because we take its initial position to be the origin, and I took the downward direction to be negative.)

3 0

3 years ago