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3 years ago

A statement made prior to an experiment, and based on little scientific evidence, is

1 answer:

7 0

A- hypothesis
You usually write hypothesis in science it’s something that can usually be tested.

B- prediction
Made before you do an science experiment, they’re usually like what you think could happen or will happen.

C- theory
Theses aren’t used with scientific evidence, they’re usually things that people believe happened. Example: Some believe Big Foot is real. But no one will ever know because its a theory

D- is already been eliminated, not all are right.

Answer is A

Hope this helped :)

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Questions for 1.21 physics lab report

Lapatulllka [165]

Ok cool dude bro I just need to answer a question

6 0

3 years ago

An object moving on a horizontal, frictionless surface makes a glancing collision with another object initially at rest on the s

cluponka [151]

Answer:

Momentum is always conserved, and kinetic energy may be conserved.

Explanation:

For an object moving on a horizontal, frictionless surface which makes a glancing collision with another object initially at rest on the surface, the type of collision experienced by this objects can either be elastic or an inelastic collision depending on whether the object sticks together after collision or separates and move with a common velocity after collision.

If the body separates and move with a common velocity after collision, the collision is elastic but if they sticks together after collision, the collision is inelastic.

Either ways the momentum of the bodies are always conserved since they will always move with a common velocity after collision but their kinetic energy may or may not be conserved after collision, it all depends whether they separates or stick together after collision and since we are not told in question whether or not they separate, we can conclude that their kinetic energy "may" be conserved.

6 0

3 years ago

An electron is confined to a one dimensional infinite potential well 150 pm. How much energy must it absorb if it is to jump to

igor_vitrenko [27]

Answer:

\Delta E=1.22\times 10^{-22}J

Explanation:

The energy of electron in any state is given by $E=\frac{n^2h^2}{8mL^2}$ here h is planck's constant n is state of electron L is the infinte potential well m is the mass of electron

We know that $h=6.67\times 10^{-34}$

Potential well dimension = $150pm=150\times 10^{-12}m$

Mass of electron $=9.1\times 10^{-31}kg$

So energy required to electron to jump from ground state to 3rd state

$\Delta E=\frac{h^2}{8mL^2}\left ( 3^2-1^2 \right )$

$\Delta E=\frac{\left ( 6.67\times 10^{-34} \right )^2}{8\times 9.1\times 10^{-31}(150\times 10^{-12})^2}\left ( 9-1 \right )$

$\Delta E=1.22\times 10^{-22}J$

7 0

3 years ago

A car traveling on a flat (unbanked) circular track accelerates uniformly from rest with a tangential acceleration of 1.7 m/s^2.

Komok [63]

Answer:

The coefficient of static friction between the car and the track

u=0.572

Explanation:

We don't know the mass of the car or any other information so the acceleration is the reason to solve the friction coefficient

∑ $F=F_{f}=m*a_{t}$

As we know

$F_{f}=u*F_{N}=u*m*g$

Also the center ward direction forces

$F_{fc}=m*a_{c}$

$a_{c}=\frac{v_{t}^2}{r}$

$F_{fc}=m*\frac{v_{t}^2}{r}$

But now vt relation with the tangential acceleration

$v_{t}=2*a_{t}*\frac{\pi }{r}$

replacing

$F_{fc}=m*a_{t}*\frac{2\pi*r}{2r}$

$F_{fc}=m*a_{t}*\pi$

So magnitude of the force can get by

$F_{f}=\sqrt{(m*a_{t}*\pi)^{2}+(m*a_{t})^{2}}$

Get the factor to simplify

$F_{f}=a_{t}*m*\sqrt{(1+\pi^2)}$

$u*m*g=m*a_{t}*(\sqrt{1+\pi^2})$

Solve to u'

$u=\frac{a_{t}}{g}*(\sqrt{1+\pi^2})$

$u=\frac{17\frac{m}{s^2} }{9.8\frac{m}{s^2}}*(\sqrt{1+\pi^2})=0.572$

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3 years ago

kiruha [24]

Answer:

The given figure shows two men M and N facing two flat and hard walls, wall 1 and wall 2. Man N fires a gun. Man M hears two echoes, one from wall 1 and second from wall 2. The speed of sound in

air is given to be 325 m/s. After the firing of the gun by the man N, the man M will hear the first echo in how many seconds?

5 0

2 years ago