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3 years ago

A net downward force of 20 N causes a book to fall towards the ground at m/s2. What is the book’s mass? Consider air resistance

Physics

1 answer:

stira [4]3 years ago

4 0

If we have to figure air resistance into it, then we don't have enough information to find an answer.

If the air around it is going to have an effect on how it falls, then it'll depend on the thickness of the book, the shape of the book, whether it's a hard-cover or soft-cover, how far the covers stick out past the pages, how smooth or rough the covers are, how bumpy the binding it. and what position you hold it in before you let it go.

(THAT's why we always ignore air resistance, especially when the question is actually about gravity anyway.)

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A beam of light strikes a sheet of glass at an angle of 56.6° with the normal in air. You observe that red light makes an angle

Yuri [45]

Answer:

(a). Index of refraction are $n_{red}$ = 1.344 & $n_{violet}$ = 1.406

(b). The velocity of red light in the glass $v_{red} =$ 2.23 × $10^{8} \ \frac{m}{s}$

The velocity of violet light in the glass $v_{violet} =$ 2.13 × $10^{8} \ \frac{m}{s}$

Explanation:

We know that

Law of reflection is

$n_1 \sin\theta_{1} = n_2 \sin\theta_{2}$

Here

$\theta_1$ = angle of incidence

$\theta_2$ = angle of refraction

(a). For red light

1 × $\sin 56.6$ = $n_{red}$ × $\sin 38.4$

$n_{red}$ = 1.344

For violet light

1 × $\sin 56.6$ = $n_{violet}$ × $\sin 36.4$

$n_{violet}$ = 1.406

(b). Index of refraction is given by

$n = \frac{c}{v}$

$n_{red}$ = 1.344

$v_{red} = \frac{c}{n_{red} }$

$v_{red} = \frac{3(10^{8} )}{1.344}$

$v_{red} =$ 2.23 × $10^{8} \ \frac{m}{s}$

This is the velocity of red light in the glass.

The velocity of violet light in the glass is given by

$v_{violet} = \frac{3(10^{8} )}{1.406}$

$v_{violet} =$ 2.13 × $10^{8} \ \frac{m}{s}$

This is the velocity of violet light in the glass.

8 0

3 years ago

If an object is dropped from a tall building and hits the ground 3.0 s. later, what is the magnitude of the object's displacemen

marin [14]

Find the velocity of the object after one second.

v = vo + at

v = (0 m/s) + (9.8 m/s^2)(1 s)

v = 9.8 m/s

Now, using that, you can find the displacement in that one second between 1 and 2.

d = vot + (1/2)at^2

d = (9.8 m/s)(1 s) + (1/2)(9.8 m/s^2)(1 s)^2

d = 14.7 m

5 0

3 years ago

Read 2 more answers

Water is flowing through a channel that is 12m wide with a

Alexus [3.1K]

Answer:

Velocity from second channel will be 1.6875 m/sec

Explanation:

We have given width of the channel , that is diameter of the channel 1 $d_1$ = 12 m

So radius $r_1=\frac{d_1}{2}=\frac{12}{2}=6m$

Speed through the channel 1 $v_1=0.75m/sec$

Width , that is diameter of the channel 2 $d_2=4m$

So $r_2=2m$

From continuity equation

$A_1v_1=A_2v_2$

$\pi \times 12^2\times 0.75=4\times \pi\times 4^2\times v_2$

$v_2=1.6875m/sec$

So velocity from smaller channel will be 1.6875 m /sec

6 0

3 years ago

Two bodies made of the same material have same external dimension and appearance, but one is compact solid and other is hollow.

Bumek [7]

Answer:

Different

Explanation:

The hollow one will expand even more making it have a larger volume then the solid one so they are different

5 0

3 years ago

The ratio of the output work to input force is the _ of the machine ?

Colt1911 [192]

<h3><u>Answer;</u></h3>

Mechanical advantage

<h3><u>Explanation;</u></h3>

Mechanical advantage is the ratio of force output from a machine divided by the force input into the machine.
Mechanical advantage measures the machine's force-magnifying effect. It is an advantage gained by using simple machines to accomplish work with less effort.
The formula is; M.A = output force/ Input force

3 0

3 years ago

Read 2 more answers