All categories

4 years ago

Please help with 3 questions about acceleration

Physics

1 answer:

Goryan [66]4 years ago

5 0

A great, helpful, useful definition of acceleration is

<em>A = (change in speed) / (time for the change)</em> . <== you should memorize this

This simple tool will directly solve all 3 problems.

The REASON for assigning these problems for homework is NOT to find the answers. It's to help YOU find out whether you know this definition, to let you go back and review it if you don't, and to give you a chance to practice using it if you do. Noticed that if you get the answers from somebody else, you lose all of these benefits.

The only wrinkle anywhere here is in #3, because when you use this definition, the unit of time has to be the same in both the numerator and the denominator.

So for #3, you have to EITHER change the km/hr to km/sec, OR change the 4sec to a fraction of an hour, before you plug anything into the definition.

You might be interested in

in the presence of air drag, an object of mass 0.126kg falls from height of 15.2m to 7.9m with the terminal speed v. How much wo

Nuetrik [128]

Answer:

Explanation:

The distance traveled is 15.2 - 7.9 = 7.3 m

The potential energy converted that is not expressed as kinetic energy is the work of air friction

W = PE - KE

W = mgh - ½mv²

W = 0.126(9.8)(7.3) - ½(0.126)v²)

W = 9.01404 - 0.063v² J

4 0

3 years ago

An AP Physics student is attempting an FRQ problem. They arrive at the following expression for the total distance an object has

zysi [14]

The student's answer is wrong because the unit of his answer is meter - seconds which is not unit of distance (meter).

<h3>Total distance traveled by an object</h3>

The total distance traveled by an object projected upward is calculated from third equation of motion a shown below.

<h3>Equation for the motion of the object</h3>

v² = u² - 2gh

where;

v is final velocity
u is initial velocity
g is acceleration due to gravity

at maximum height, the final velocity is zero, v = 0

0 = u² - 2gh

2gh = u²

h = u²/2g

The equation for the total distance an object has traveled during upward projection is "h = u²/2g".

<h3>Dimension of the student's answer;</h3>

d = (2vh)/g = (m/s x m) / (m/s²) = (m²/s) / (m/s²) = m.s

Thus, the student's answer is wrong because the unit of his answer is meter - seconds which is not unit of distance (meter).

Learn more about distance here: brainly.com/question/2854969

#SPJ1

7 0

2 years ago

When an electron de-excites from the third quantum level to the second, and then to the ground state, two photons are emitted. T

Leokris [45]

Answer:

ground state

Explanation:

Lets take

n=3 ,n=2 ,n=1 are the energy level.

Energy level n=1 is the ground energy level.

The energy from 3 to 1 = hν

The energy from 3 to 2 = hν₁

The energy from 2 to 1 = hν₂

We can say that

hν = hν₁ + hν₂

If the electron were de-excitation from the third level to ground level then the sum of emitted frequency will be equal to the frequency of a single electron.

Therefore the answer is ground state.