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3 years ago

Time for some gravity! Except if have no idea what’s going on, could someone help? :)

Physics

2 answers:

iVinArrow [24]3 years ago

4 0

1). C

2). D

3). B

4). A

5). D

6). B

7). C

8). A

9). B

10). B

allochka39001 [22]3 years ago

3 0

Answer: number 2 I think is d all of the above

Explanation: the teacher explained it to the class that.

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A box of mass 20kg is pulled up an inclined plane by a force of 285N. Given that the value of the incline angle is 30 degrees an

docker41 [41]

Given :

Mass of box , m = 250 kg.

Force applied , F = 285 N.

The value of the incline angle is 30°.

the coefficient of dynamic friction is $\mu=0.72$ .

To Find :

The speed with which the box is moving with, assuming it takes 4 seconds to reach the top of the incline.

Solution :

Net force applied in box is :

$F=285 - mgsin\ \theta - \mu mg cos \ \theta\\ \\F=285-mg( sin \ \theta - \mu cos\ \theta)\\\\F=285 - 20\times 10( \dfrac{1}{2}+0.72\times \dfrac{\sqrt{3}}{2})\\\\F=60.29\ N$

Acceleration , $a=\dfrac{F}{m}=\dfrac{60.29}{20}=3.01\ m/s^2$ .

By equation of motion :

$v=u+at\\\\v=0+3.01\times 4\\\\v=12.04\ m/s$

Therefore, the speed of box is 12.04 m/s.

Hence, this is the required solution.

6 0

3 years ago

In a power plant, pipes transporting superheated vapor are very common. Superheated vapor flows at a rate of 0.3 kg/s inside a p

grigory [225]

Answer: $h=160.84 W/m^2-K$

Explanation:

Given

mass flow rate=0.3 kg/s

diameter of pipe=5 cm

length of pipe=10 m

Inside temperature=22

Pipe surface =100

Temperature drop=30

specific heat of vapor(c)=2190 J/kg.k

heat supplied $Q=mc\Delta T=0.3\times 2190\times (30)$

Heat due to convection =hA(100-30)

$A=\pi d\cdot L$

$A=\pi 0.05\times 10=1.571 m^2$

$Q_{convection}=h\times 1.571\times (100-22)=122.538 h$

$Q=Q_{convection}$

19,710=122.538 h

$h=160.84 W/m^2-K$

5 0

3 years ago

A house is wired so that one electrical source comes to a room but many outlets and lights work from that source. When one light

Lyrx [107]

Its parallel, did this help?

6 0

4 years ago

On a speed-time graph, a horizontal line shows the change in speed is ____.

spayn [35]

On a speed/time graph, the height of the line at any point
shows the speed at that moment. If the line is horizontal,
then its height isn't changing, meaning that the speed isn't
changing. It's constant. The change is zero, until the line
starts rising or falling.

4 0

4 years ago

Two physics students are standing on skateboards and facing each other. Their masses, including the skateboards, are 95 kg and 5

andrey2020 [161]

Answer:

1) $\sum \vec p=0\ kg.m.s^{-1}$

2) $v_2=55.078\ m.s^{-1}$

Explanation:

Given:

mass of heavier student, $m_1=95\ kg$

mass of lighter student, $m_2=58\ kg$

velocity of the heavier student after the mutual push, $v_1=3.1\ m.s^{-1}$

Since they push each other and we are neglecting any friction that means we can consider this as a perfectly elastic collision. So the momentum of the two bodies will be equal and in opposite direction.

Since momentum is a vector quantity so the total momentum of the system as a whole will be zero.

<u>From the condition of elastic collision:</u>

$p_1=p_2$

$m_1.v_1=m_2.v_2$

$95\times 3.1=58\times v_2$

$v_2=55.078\ m.s^{-1}$

6 0

4 years ago