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4 years ago

"What is the mass in kg of a 3920N piano?" Which formula would this question use? F=ma or W=mg?

1 answer:

7 0

W = mg, because you have the weight of the piano and if you just divide it by g that will give you the mass you need. The piano isn't accelerating right now in a way that you'd need to use F = ma.

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Marie observed people at a store. Which is a qualifier observation she may have made ?

leva [86]

Complete question is;

Marie observed people at a store. Which is a qualitative observation she may have made?

A. Twenty people walked into the store.

B. The store sells clothes.

C. It was 1:00 P.M.

D. all of the above

Answer:

Option B:The store sells clothes.

Explanation:

We want to find the one that is a qualitative observation;

Looking at the options;

A. Twenty people walked into the store. This denotes a quantitative measure because of the number 20.

B. The store sells clothes. This denotes a qualitative measure because it describes what she sells.

C. This is a quantitative measure because it deals with time of 1 pm which is quantitative.

Therefore, the correct answer is Option B

6 0

3 years ago

What is the maximum kinetic energy of electrons ejected from barium when illuminated by white light, to 750 nm?

Ugo [173]

Answer:

$1.0045\times10^{-19}$ J

Explanation:

The complete statement is given as

What is the maximum kinetic energy of electrons ejected from barium (Wo = 2.48 eV) when illuminated by white light, 400 nm to 750 nm ?

$\lambda$ = wavelength of the white light = 400 nm = 400 x 10⁻⁹ m

$c$ = speed of white light = 3 x 10⁸ ms⁻¹

Energy of the white light is given as

$E = \frac{hc}{\lambda} = \frac{(6.63\times10^{-34})(3\times10^{8})}{400\times10^{-9}}\\E = 4.9725\times10^{-19} J$

$W_{o}$ = Work function of barium = 2.48 eV = 2.48 x 1.6 x 10⁻¹⁹ J

$K$ = Maximum kinetic energy

Using photoelectric equation we have

$E = W_{o} + K\\4.9725\times10^{-19} = 2.48\times1.6\times10^{-19} + K\\K = 1.0045\times10^{-19} J$

3 0

3 years ago

In the figure, a weightlifter's barbell consists of two identical small but dense spherical weights, each of mass 50 kg. These w

kondaur [170]

The moment of inertia is $24.8 kg m^2$

Explanation:

The total moment of inertia of the system is the sum of the moment of inertia of the rod + the moment of inertia of the two balls.

The moment of inertia of the rod about its centre is given by

$I_r = \frac{1}{12}ML^2$

where

M = 24 kg is the mass of the rod

L = 0.96 m is the length of the rod

Substituting,

$I_r = \frac{1}{12}(24)(0.96)^2=1.84 kg m^2$

The moment of inertia of one ball is given by

$I_b = mr^2$

where

m = 50 kg is the mass of the ball

$r=\frac{L}{2}=\frac{0.96}{2}=0.48 m$ is the distance of each ball from the axis of rotation

So we have

$I_b = (50)(0.48)^2=11.5 kg m^2$

Therefore, the total moment of inertia of the system is

$I=I_r + 2I_b = 1.84+ 2(11.5)=24.8 kg m^2$

Learn more about inertia:

brainly.com/question/2286502

brainly.com/question/691705

#LearnwithBrainly

6 0

3 years ago

Current cannot flow through a circuit when the switch is _____.

Akimi4 [234]

Answer:

Open

Closed

Explanation:

An open circuit is an electrical circuit in which the electric current does not circulate because it is interrupted or not communicated by means of an electrical conductor. While in a closed circuit, the current, that is the flow of electrons, travels from the beginning of the circuit to the end.

4 0

3 years ago

Read 2 more answers

How do you know there is current in a circuit?

Ksivusya [100]

if there is not a reaction

5 0

3 years ago