All categories

3 years ago

Electromagnetic waves can transfer energy without a(n) _____________ (medium/electric field).

1 answer:

7 0

Medium.
Medium is matter, and electromagnetic waves do not need matter to travel. Just like the sun, its plasma light travels across space to reach us.

You might be interested in

During a game the same batter swings at a ball thrown by the pitcher and hits a line drive. Just before the ball is hit it is tr

sergeinik [125]

Answer:

The total work on the ball is 36.25 Joules

Explanation:

There is an important principle on classical mechanics that is the work-energy principle it states that the total work on an object is equal the change on its kinetic energy, mathematically expressed as:

$W_{net}=\Delta K = K_f -K_i$ (1)

With W net the total work, Kf the final kinetic energy and Ki the initial kinetic energy. We're going to use this principle to calculate the total work on the baseball by the force exerted by the bat.

Kinetic energy is the energy related with the movement of an object and every classical object with velocity has some kinetic energy, it is defined as:

$K=\frac{mv^2}{2}$

With m the mass of the object and v its velocity, knowing this we can use on:

$W_{net}= \frac{mv_f^2 -mv_i^2}{2}=\frac{m(v_f^2 -v_i^2)}{2}$

In our case vf is the velocity just after the hit and vi the velocity just before the hit. For an average baseball its mass is 145g that is 0.145 kg, then

$W_{net}=\frac{0.145*(30.0^2 -20.0^2)}{2}$

$W_{net}=36.25 J$

8 0

3 years ago

When you throw a ball, the work you do to accelerate it equals the kinetic energy the ball gains. If you do twice as much work w

aniked [119]

Answer:

No. Twice as much work will give the ball twice as much kinetic energy. But since KE is proportional to the speed squared, the speed will be $sqrt{2}$ times larger.

Explanation:

The work done on the ball is equal to the kinetic energy gained by the ball:

$W=K$

So when the work done doubles, the kinetic energy doubles as well:

$2W = 2 K$

However, the kinetic energy is given by

$K=\frac{1}{2}mv^2$

where

m is the mass of the ball

v is its speed

We see that the kinetic energy is proportional to the square of the speed, $v^2$ . We can rewrite the last equation as

$v=\sqrt{\frac{2K}{m}}$

which also means

$v=\sqrt{\frac{2W}{m}}$

If the work is doubled,

$W'=2W$

So the new speed is

$v'=\sqrt{\frac{2(2W)}{m}}=\sqrt{2}\sqrt{\frac{2W}{m}}=\sqrt{2} v$

So, the speed is $\sqrt{2}$ times larger.

5 0

3 years ago

If the velocity of an object is 9 m/s and its momentum is 72 kgm/s, what is its mass

MAVERICK [17]

An object with a velocity (v) of 9 m/s and a linear momentum (p) of 72 kg.m/s, has a mass (m) of 8 kg.

<h3>What is momentum?</h3>

In Newtonian mechanics, linear momentum, or simply momentum, is the product of the mass and velocity of an object.

It is a vector quantity, possessing a magnitude and a direction.

The mathematical expression for momentum is:

p = m . v

where,

p is the linear momentum of the object.
m is the mass of the object.
v is the velocity of the object.

An object has a velocity (v) of 9 m/s and its linear momentum (p) is 72 kg.m/s. We will use the definition of linear momentum to calculate the mass of the object.

p = m . v

m = p / v

m = (72 kg.m/s) / (9 m/s) = 8 kg

An object with a velocity (v) of 9 m/s and a linear momentum (p) of 72 kg.m/s, has a mass (m) of 8 kg.

Learn more about linear momentum here: brainly.com/question/7538238

#SPJ1

5 0

2 years ago

I Need Assistance With This Equation:

nikklg [1K]

Check the picture below.

now, for 6 triangles, well, simply 6*6.

8 0

3 years ago

How do you measure the wavelength of a transverse wave?

DENIUS [597]

By looking at how wiggily the bar is lol

8 0

4 years ago