In order to reduce the amount of energy lost due to heat flow, electricity is delivered to our homes using ____

The gravitational attraction between two objects will what is the object move further apart

finlep [7]

The farther apart the two objects, the weaker the gravitational attraction between them.

3 0

3 years ago

If the kinetic energy of a 32kg box is 1500 J just before it hits the ground, from what height was it dropped?If the kinetic ene

statuscvo [17]

Answer:

4.8 m

Explanation:

When it hits the ground, all the kinetic energy is converted to potential energy. Potential energy, PE is given by mgh where m is the mass of the box, g is acceleration due to gravity and h is the height which is unknown for this case

PE=mgh and making h the subject of the formula then $h=\frac {PE}{mg}$ and substituting g with 9.81, PE with 1500 J and m with 32 kg then

$h=\frac {1500}{32\times 9.81}=4.7782874617734m\approx 4.8 m$

6 0

4 years ago

Eight 7.0W Christmas tree lights are strung in series to a 110 V light source. What is the resistance of each bulb?

Evgesh-ka [11]

Answer:

Resistance = 1728.57 Ohms

Explanation:

Given the following data;

Power = 7 Watts

Voltage = 110 Volts

To find the resistance of each bulb;

Mathematically, power can be calculated using the formula;

$Power = \frac {Voltage^{2}}{resistance}$

Making resistance the subject of formula, we have;

$Resistance = \frac {Voltage^{2}}{power}$

Substituting into the formula, we have;

$Resistance = \frac {110^{2}}{7}$

$Resistance = \frac {12100}{7}$

Resistance = 1728.57 Ohms

8 0

3 years ago

The 20 kg at angle of 53⁰ in an inclined plane is realsed from rest the coefficient of friction bn the block and the inclined pl

Scorpion4ik [409]

Given :-

A 20kg block at an angle 53⁰ in an inclined plane is released from rest .
$\mu_s = 0.3 \ \& \ \mu_k = 0.2$

To Find :-

Would the block move ?
If it moves what is its speed after it has descended a distance of 5m down the plane .

Solution :-

For figure refer to attachment .

So the block will move if the angle of the inclined plane is greater than the angle of repose . We can find it as ,

$\longrightarrow \theta_{repose}= tan^{-1}(\mu_s)$

Substitute ,

$\longrightarrow \theta_{repose}= tan^{-1}( 0.2)$

Solve ,

$\longrightarrow\underline{\underline{\theta_{repose}= 16.6^o }}$

Hence ,

$\longrightarrow\theta_{plane}>\theta_{repose}$

Hence the block will slide down .

Now assuming that block is released from the reset , it's initial velocity will be 0m/s .

And the net force will be ,

$\longrightarrow F_n = mgsin53^o - \mu_k N$

Substitute, N = mgcos53⁰ ( see attachment)

$\longrightarrow ma_n = mgsin53^o - \mu_k mgcos53^o$

Take m as common,

$\longrightarrow\cancel{m }(a_n) = \cancel{m}( gsin53^o - \mu gcos53^o)$

Simplify ,

$\longrightarrow a_n = gsin53^o - \mu_k g cos53^o$

Substitute the values of sin , cos and g ,

$\longrightarrow a_n = 10( 0.79 - 0.2 (0.6))$

Simplify ,

$\longrightarrow a_n = 10 ( 0.79 - 0.12 ) \\\\ \longrightarrow a_n = 10 (0.67)\\\\ \longrightarrow \underline{\underline{a_n = 6.7 m/s^2}}$

Now using the Third equation of motion namely,

$\longrightarrow2as = v^2-u^2$

Substituting the respective values,

$\longrightarrow2(6.7)(5) = v^2-(0)^2$

Simplify and solve for v ,

$\longrightarrow v^2 = 67 m/s\\\\\longrightarrow v =\sqrt{67} m/s \\\\\longrightarrow\underline{\underline{ v = 8.18 m/s }}$

Hence the velocity after covering 5m is 8.18 m/s .

7 0

3 years ago

Convection currents occur when _________ energy transfers between two parts of a fluid

valentinak56 [21]

Answer:

heat

Explanation:

7 0

3 years ago

In order to reduce the amount of energy lost due to heat flow, electricity is delivered to our homes using _____.