All categories

3 years ago

Help.. mee.. ;-; Dont answer if you dont know I dont want to fail this

Physics

2 answers:

timama [110]3 years ago

5 0

Answer:

It would be B because the warm air heats up and then burns the marshmallow. And the heat and the marshmallow were touching each other

Explanation:

Arte-miy333 [17]3 years ago

3 0

Answer:

its B because both objects are touching, every other option the heat moves through the air

You might be interested in

When a bow is stretched back and an arrow is shot what type of energy conversion has occured

Vesna [10]

Elastic to kinetic energy. Bow elastic transfered to arrow kinetic energy

4 0

4 years ago

Rutherford discovered the nucleus of the atom by firing a particles at gold foil. An a particle has a charge of q = +2e and a ma

Readme [11.4K]

Answer: $r_0=3.037\times 10^{-14}m$

Explanation:

Given

charge on alpha particle=+2e

mass of alpha particle= $6.64\times 10^{-27}$ kg

Charge on gold nucleus=+79e

Velocity at r=1m is $1.9\times 10^{7}$

Using Energy conservation

Kinetic energy of particle will be converting to Potential energy as it approaches to nucleus

therefore

$\frac{1}{2}mv^2+U_{r=1m}=U_{closest\ to\ nucleus}$

$\frac{1}{2}\left ( 6.64\times 10^{-27}\right )\left ( 1.9\times 10^{7}^2\right )+\frac{K\left ( 2e\right )\left ( 79e\right )}{1}=\frac{K\left ( 2e\right )\left ( 79e\right )}{r_0}$

$\frac{1}{2}\left ( 6.64\times 10^{-27}\right )\left ( 1.9\times 10^{7}^2\right )=\frac{9\times 10^9\times 158\times \left ( 1.6\times 10^{-19}\right )}{y}\left [\frac{1}{r_0}-\frac{1}{1}\right ]$

on solving we get

$\frac{1}{r_0}=3.292\times 10^{13}$

$r_0=3.037\times 10^{-14}m$

8 0

3 years ago

Two children of mass 18 kg and 29 kg sit balanced on a seesaw with the pivot point located at the center of the seesaw. If the c

DedPeter [7]

Answer:

3.085 [m].

Explanation:

1) The rule:

m₁*g*l₁=m₂*g*l₂, where m₁ and l₁ - the mass and distance for the small child, m₂ and l₂ - for the big child;

2) according to the condigion l₁+l₂=5, then

3) it is possible to make up the system:

$\left \{ {{l_1+l_2=5} \atop {m_1*l_1=m_2*l_2}} \right. \ = > \ \left \{ {{l_1=5-l_2} \atop {18*(5-l_2)=29*l_2}} \right. \ = > \ \left \{ {{l_1=\frac{145}{47}} \atop {l_2=\frac{90}{47}}} \right.$

4) finally, l₁=145/47≈3.085 [m].

7 0

2 years ago

The electric field in a region of space increases from 0 to 2150 N/C in 5.00 s. What is the magnitude of the induced magnetic fi

Feliz [49]

To solve this problem we will use the Ampere-Maxwell law, which describes the magnetic fields that result from a transmitter wire or loop in electromagnetic surveys. According to Ampere-Maxwell law:

$\oint \vec{B}\vec{dl} = \mu_0 \epsilon_0 \frac{d\Phi_E}{dt}$

Where,

B= Magnetic Field

l = length

$\mu_0$ = Vacuum permeability

$\epsilon_0$ = Vacuum permittivity

Since the change in length (dl) by which the magnetic field moves is equivalent to the perimeter of the circumference and that the electric flow is the rate of change of the electric field by the area, we have to

$B(2\pi r) = \mu_0 \epsilon_0 \frac{d(EA)}{dt}$

Recall that the speed of light is equivalent to

$c^2 = \frac{1}{\mu_0 \epsilon_0}$

Then replacing,

$B(2\pi r) = \frac{1}{C^2} (\pi r^2) \frac{d(E)}{dt}$

$B = \frac{r}{2C^2} \frac{dE}{dt}$

Our values are given as

$dE = 2150N/C$

$dt = 5s$

$C = 3*10^8m/s$

$D = 0.440m \rightarrow r = 0.220m$

Replacing we have,

$B = \frac{r}{2C^2} \frac{dE}{dt}$

$B = \frac{0.220}{2(3*10^8)^2} \frac{2150}{5}$

$B =5.25*10^{-16}T$

Therefore the magnetic field around this circular area is $B =5.25*10^{-16}T$

3 0

3 years ago

What is neant by velocity ratio of machine is 3 and efficency is 60%

Kisachek [45]

Answer:

Velocity ratio of a lever is 3 means distance travelled by effort is 3 times the distance travelled by the load. Efficiency of the pulley is 60%means 40% of the energy is lost in the machine due to the friction

3 0

3 years ago

Read 2 more answers