Ork is done if a boat has a force 60N and travels 600 meters

A pitcher can throw a baseball at about 90 miles/hour (about 39.6 m/s). What is the ratio of the kinetic energy to the rest ener

tester [92]

Answer:

$8.71*10^{-15}$

Explanation:

The rest energy is the energy associated with the base ball at zero velocity which is expressed as

$Rest energy=mc^{2}\\$

Note: the speed C is the speed of light which is expressed as 3*10^8

while the kinetic energy is the energy associated with the ball during its motion and is expressed as

$Kinetic energy=1/2mv^{2}$

the ratio can be expressed as

$\frac{Kinetic Energy}{Rest Energy}=\frac{\frac{1}{2}mv^{2} }{mc^{2}}\\since V=39.6m/s\\C=3*10^{8}m/s\\\frac{Kinetic Energy}{Rest Energy}=\frac{\frac{1}{2}39.6^{2} }{(3*10^8)^{2}} \\\frac{Kinetic Energy}{Rest Energy}=\frac{784.08}{9*10^{16}} \\\frac{Kinetic Energy}{Rest Energy}=8.71*10^{-15}$

5 0

4 years ago

A 85-kg astronaut is stranded from his space shuttle. He throws a 1-kg hammer away from the shuttle with a velocity of 17 m/s. H

algol [13]

Answer:

0.2 m/s

Explanation:

given,

mass of astronaut, M = 85 Kg

mass of hammer, m = 1 Kg

velocity of hammer , v =17 m/s

speed of astronaut, v' = ?

initial speed of the astronaut and the hammer be equal to zero = ?

Using conservation of momentum

(M + m) V = M v' + m v

(M + m) x 0 = 85 x v' + 1 x 17

85 v' = -17

v' = -0.2 m/s

negative sign represent the astronaut is moving in opposite direction of hammer.

Hence, the speed of the astronaut is equal to 0.2 m/s

4 0

3 years ago

A football is kicked straight up from a height of 5 feet with an initial speed of 55 feet per second. The formula h equals negat

makvit [3.9K]

Answer:

3.53 second

Explanation:

The formula for the height is

$h=-16t^{2}+55t+5$

When it hits the ground, the height is zero.

So, put h = 0 in the above equation

$0=-16t^{2}+55t+5$

$16t^{2}-55t-5=0$

$t=\frac{+55\pm \sqrt{55^{2}+4\times 5\times 16}}{2\times 16}$

$t=\frac{+55\pm 57.84}{2\times 16}$

Take positive sign

t = 3.53 second.

Thus, the time taken to hit the ground is 3.53 second.

8 0

3 years ago

The train with a mass of 49 kg × 10⁴ kg departs from the place and in 25 seconds reaches a speed of 5m / s, determine the attrac

mote1985 [20]

Answer:

Read this entry from a blog about service dogs.

Lexie, an eight-month-old black Labrador retriever, is sleeping quietly at my feet. I can’t help but think that her soft, velvety ears and alert brown eyes would make her the perfect “doggie model” for pet magazines and pet store ads. However, Lexie will soon have a much more important job to do. In a few months, she will become the loyal companion and service dog for a young man who has been blind since birth. She will help him board public transportation, such as buses, subways, and trains, and she will help him safely cross busy intersections. Lexie will even help the young man avoid obstacles, such as high curbs and low overhangs. Like all dogs in our organization, Lexie has undergone months of specialized training to help a visually impaired person lead an active and independent life.

What is the secondary purpose of this blog?

to inform readers about seeing-eye dogs

to entertain readers with details about Lexie

to persuade readers to train service dogs

to convince readers to adopt Labrador retrievers

Explanation:

5 0

3 years ago

Which of the following statements is consistent with Thomson’s and Millikan’s work with cathode rays and electrons? (A) Cathode

victus00 [196]

Answer:

Dalton's ideas proved foundational to modern atomic theory. However, one of his underlying assumptions was later shown to be incorrect. Dalton thought that atoms were the smallest units of matter-−minustiny, hard spheres that could not be broken down any further. This assumption persisted until experiments in physics showed that the atom was composed of even smaller particles. In this article, we will discuss some of the key experiments that led to the discovery of the electron and the nucleus.

J.J. Thomson and the discovery of the electron

In the late 19^{\text{th}}19

th

19, start superscript, start text, t, h, end text, end superscript century, physicist J.J. Thomson began experimenting with cathode ray tubes. Cathode ray tubes are sealed glass tubes from which most of the air has been evacuated. A high voltage is applied across two electrodes at one end of the tube, which causes a beam of particles to flow from the cathode (the negatively-charged electrode) to the anode (the positively-charged electrode). The tubes are called cathode ray tubes because the particle beam or "cathode ray" originates at the cathode. The ray can be detected by painting a material known as phosphors onto the far end of the tube beyond the anode. The phosphors spark, or emit light, when impacted by the cathode ray.

A diagram of a cathode ray tube.

A diagram of J.J. Thomson's cathode ray tube. The ray originates at the cathode and passes through a slit in the anode. The cathode ray is deflected away from the negatively-charged electric plate, and towards the positively-charged electric plate. The amount by which the ray was deflected by a magnetic field helped Thomson determine the mass-to-charge ratio of the particles. Image from Openstax, CC BY 4.0.

To test the properties of the particles, Thomson placed two oppositely-charged electric plates around the cathode ray. The cathode ray was deflected away from the negatively-charged electric plate and towards the positively-charged plate. This indicated that the cathode ray was composed of negatively-charged particles.

Thomson also placed two magnets on either side of the tube, and obser

Explanation:

5 0

3 years ago