A radio changes what energy to what energy

Hannah walks 0.30 km to class in 5.0 min. what is her average speed in m/s?

OverLord2011 [107]

Answer:

1.0 m/s

Explanation:

First, convert to SI units.

0.30 km × (1000 m / km) = 300 m

5.0 min × (60 s / min) = 300 s

Speed is distance divided by time:

300 m / 300 s = 1.0 m/s

3 0

3 years ago

A plastic rod 1.3 m long is rubbed all over with wool, and acquires a charge of -3e-08 coulombs. we choose the center of the rod

Anestetic [448]

(a) The plastic rod has a length of L=1.3m. If we divide by 8, we get the length of each piece:
$L/8=1.3m/8=0.1625 m$

(b) The center of the rod is located at x=0. This means we have 4 pieces of the rod on the negative side of x-axis, and 4 pieces on the positive side. So, starting from x=0 and going towards positive direction, we have: piece 5, piece 6, piece 7 and piece 8. Each piece is 0.1625 m long. Therefore, the center of piece 5 is at 0.1625m/2=0.0812 m. And the center of piece 6 will be shifted by 0.1625m with respect to this:
$c_6 = 0.0812m+0.1625m=0.2437 m$

(c) The total charge is $Q=-3 \cdot 10^{-8}C$ . To get the charge on each piece, we should divide this value by 8, the number of pieces:
$Q/8=-3\cdot 10^{-8}C/8=-3.75\cdot 10^{-9}C$

(d) We have to calculate the electric field at x=0.7 generated by piece 6. The charge on piece 6 is the value calculated at point (c):
$q= -3.75\cdot 10^{-9}C$
If we approximate piece 6 as a single charge, the electric field is given by
$E=k_e \frac{q}{d^2}$
where $k_e=8.99\cdot 10^9Nm^2C^{-2}$ and d is the distance between the charge (center of piece 6, located at 0.2437m) and point a (located at x=0.7m). Therefore we have
$E= 8.99\cdot 10^9 Nm^2C^{-2} \frac{-3.75\cdot 10^9 C}{(0.2437m-0.7m)^2} =-161.9 V/m$
poiting towards the center of piece 6, since the charge is negative.

(e) missing details on this question.

5 0

3 years ago

What in earth's atmosphere helps most to absorb uvb ultraviolet light from the sun?

Whitepunk [10]

The Ozone layer in the atmosphere absorbs the UV rays

Hope it helps!

4 0

3 years ago

The roof of a two-story house makes an angle of 29° with the horizontal. A ball rolling down the roof rolls off the edge at a sp

AlekseyPX

Answer:

$t = 0.93 s$

Part b)

$d = 3.98 m$

Part c)

$v_x = 4.28 m/s$

$v_y = -11.49 m/s$

Explanation:

The two components of the velocity of the ball is given as

$v_x = 4.9 cos29$

$v_x = 4.28 m/s$

$v_y = 4.9 sin29$

$v_y = 2.37 m/s$

Part a)

now we know that the displacement in y direction is given as

$\Delta y = 6.4 m$

so we have

$\Delta y = v_y t + \frac{1}{2}gt^2$

$6.4 = 2.37 t + 4.9 t^2$

$t = 0.93 s$

Part b)

Distance of the ball in x direction of the motion is given as

$d = v_x t$

$d = 4.28 \times 0.93$

$d = 3.98 m$

Part c)

In x direction the velocity will remain the same always

$v_x = 4.28 m/s$

while in Y direction we can use kinematics

$v_y = v_{oy} + at$

$v_y = -2.37 - 9.81(0.93)$

$v_y = -11.49 m/s$

6 0

3 years ago

How did the atomic theory develop and change

IgorC [24]

Explanation:

Early Atomic theory

Although the idea of the atom was first suggested by Democritus in the fourth century BC, his suppositions were not useful in explaining chemical phenomena, because there was no experimental evidence to support them. It was not until the late 1700's that early chemists began to explain chemical behavior in terms of the atom. Joseph Priestly, Antoine Lavoisier, and others set the stage for the foundation of chemistry. They demonstrated that substances could combine to form new materials. It was the English chemist, John Dalton, who put the pieces of the puzzle together and developed an atomic theory in 1803.

Dalton's atomic theory contains five basic assumptions:

All matter consists of tiny particles called atoms. Dalton and others imagined the atoms that composed all matter as tiny, solid spheres in various stages of motion.

Atoms are indestructible and unchangeable. Atoms of an element cannot be created, destroyed, divided into smaller pieces, or transformed into atoms of another element. Dalton based this hypothesis on the law of conservation of mass as stated by Antoine Lavoisier and others around 1785.

Elements are characterized by the weight of their atoms. Dalton suggested that all atoms of the same element have identical weights. Therefore, every single atom of an element such as oxygen is identical to every other oxygen atom. However, atoms of different elements, such as oxygen and mercury, are different from each other.

In chemical reactions, atoms combine in small, whole-number ratios. Experiments that Dalton and others performed indicated that chemical reactions proceed according to atom to atom ratios which were precise and well-defined.

When elements react, their atoms may combine in more than one whole-number ratio. Dalton used this assumption to explain why the ratios of two elements in various compounds, such as oxygen and nitrogen in nitrogen oxides, differed by multiples of each other.

John Dalton's atomic theory was generally accepted because it explained the laws of conservation of mass, definite proportions, multiple proportions, and other observations. Although exceptions to Dalton's theory are now known, his theory has endured reasonably well, with modifications, throughout the years.

7 0

3 years ago