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3 years ago

Help pls pls i give reward

Physics

2 answers:

ohaa [14]3 years ago

3 0

Answer:

Explanation:

There is no new substances formed in choice B

xz_007 [3.2K]3 years ago

3 0

Answer:

the answer is B. boiling of water, bursting of a balloon, crumpling a piece of paper.

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A stone is thrown upward from the top of a building at an angle of 30° to the horizontal and with an initial speed of 20 m/s. Th

Hitman42 [59]

Answer:

Explanation:

Given

inclination $\theta =30^{\circ}$

initial speed $u=20\ m/s$

Point of release is 45 m above the ground

Considering stone to be a projectile, so time taken by projectile for its zero vertical displacement is

$t_1=\frac{2u\sin \theta }{g}$

$t_1=\frac{2\times 20\times \sin 30}{10}$

$t_1=2\ s$

Now after completing zero vertical displacement , stone needs to travel another 45 m in downward direction with initial speed u=20\sin 30

$h=u_yt+\frac{1}{2}a_yt^2$

where, $h=height$

$u_y=vertical velocity$

$a_y=vertical acceleration$

$t_0=time$

$45=20\sin 30+\frac{1}{2}(9.8)(t_0)^2$

$t_0^2=\frac{70}{9.8}$

$t_0=2.64\ s$

thus total time time required is $t=t_0+t_1=2.64+2=4.64\ s$

vertical velocity just before hitting

$v_y=\sqrt{u_y^2+2\times a_y\times s}$

$v_y=\sqrt{10^2+2\times 10\times 45}$

$v_y=\sqrt{1000}=31.622\ m/s$

Horizontal velocity $v_x=u\cos 30=17.32\ m/s$

Net velocity Just before hitting $=\sqrt{v_x^2+v_y^2}$

$=\sqrt{(17.32)^2+(31.62)^2}$

$=\sqrt{1299.82}=36.05\ m/s$

7 0

3 years ago

If each washer has a mass of 4.9 g, then the mass of two washers in kilograms would be Given that F = ma, and if 4 washers are a

zysi [14]

Given that,

Mass of each washer = 4.9 g

We need to calculate the mass of two washers in kg

Using conversion of unit

Mass of each washer $m= 4.9\times10^{-3}\ Kg$

So, Mass of two washers is

$M=2\times m$

Put the value of m

$M=2\times4.9\times10^{-3}\ k$

$M=0.0098\ Kg$

If 4 washer are attached to the spring

We need to calculate the applied force on the car

Using formula of force

$F=mg$

Put the value into the formula

$F=4\times4.9\times10^{-3}\times9.8$

$F=0.192\ N$

Hence, (i), The mass of two washers is 0.0098 kg.

(ii). The applied force on the car is 0.192 N.

6 0

3 years ago

A horizontal force of 150 N is used to push a 40.0-kg packing crate a distance of 6.00 m on a rough horizontal surface. If the c

icang [17]

Answer:

a. 900 J

b. 0.383

Explanation:

According to the question, the given data is as follows

Horizontal force = 150 N

Packing crate = 40.0 kg

Distance = 6.00 m

Based on the above information

a. The work done by the 150-N force is

$W = F x = \mu N x = \mu\ m\ g\ x$

$W = 150 \times 6$

= 900 J

b. Now the coefficient of kinetic friction between the crate and surface is

$\mu = \frac {F}{m\timesg}$

$= \frac{150}{40\times 9.8}$

= .383

We simply applied the above formulas so that each one part could calculate

3 0

3 years ago

"Nuclear fission is the splitting of electrons in the outer shell of an atom." True or False?

sweet-ann [11.9K]

Answer:

The correct answer is:

False

Explanation:

Nuclear fission is the splitting of nucleus of an atom which results in the emission of high amount of energy.

<u>Example:</u>

Heavy atom (i.e. uranium) when bombarded with neutrons, its nucleus split into smaller lighter weight nuclei and release a huge amount of energy. (Nuclear fission also takes place without neutrons i.e. in the form of radioactive decay (the process in which an unstable nucleus of an atom releases energy in the form of radiation)).

3 0

3 years ago

Can a jail legally not give you food or water for 4 days

maks197457 [2]

Yes but they not supposed to

4 0

3 years ago