Answer:
Matter
Pure substances Mixture
Element compound Homogenous Heterogenous
<h3><u>Answer;</u></h3>
- A moving electric charge creates a magnetic field at all points in the surrounding region.
- An electric current in a conductor creates a magnetic field at all points in the surrounding region.
- A permanent magnet creates a magnetic field at all points in the surrounding region.
<h3><u>Explanation;</u></h3>
- A magnetic field can be created by running electricity through a wire. All magnetic fields are created by moving charged particles. it is important to also note that charged particles create magnetic fields only when they are moving.
- The strength of the magnetic field generated or created is proportional to the amount of current flowing through the wire. Thus, increasing the current increases the strength of the magnetic field.
The kinetic energy of the object is 392 Joules.
<span>11.823 cm
There is a slight ambiguity with this question in that I don't know if the measurements are from the surface of the ball, or the center of the ball. I will take this question literally and as such the point light source will be 124 cm from the wall.
The key thing to remember is that ball won't be showing an effective diameter of 4 cm to the light source. Instead the shadow line is a tangent to the ball's surface. There is a right triangle where the hypotenuse is the distance from the center of the ball to the light source (42 cm), one leg of the triangle is the radius (2cm). That right triangle will define a chord that will be the effective diameter of the disk casting the shadow. The cosine of the half angle of the chord will be 2/42 = 1/21. The sine of the half angle then becomes sqrt(1-(1/21)^2) = sqrt(440/441) = 2sqrt(110) = 0.99886557. Now multiply that sine by 4 (radius of ball multiplied by 2 since it's the half angle and we want the full side of the chord) and we get an effective diameter of 3.995462279 cm.
Now we need to calculate the effective distance that circle is from the wall. It will be slightly larger than 82 cm. The exact value will be 82 + cos(half angle) * radius. So
82 + 1/21 * 2 = 82 + 2/21 = 82.0952381
Now we have the following dimensions with a circle replacing the ball in the original problem.
Distance from wall to effective circle = 82.0952381 cm
Distance from effective circle to point source = 124 - 82.0952381 = 41.9047619 cm
Effective diameter of circle = 3.995462279 cm
And because the geometry makes similar triangles, the following ratio applies.
3.995462279/41.9047619 = X/124
Now solve for X
3.995462279/41.9047619 = X/124
124*3.995462279/41.9047619 = X
495.4373226/41.9047619 = X
11.82293611 = X
The shadow cast on the wall will be a circle with a diameter of 11.823 cm</span>
Answer:
Explanation:
Amount of heat required can be found from the following relation
Q = mcΔT
m is mass of the body , c is specific heat and ΔTis rise in temperature .
Here m = 300 kg
c = 3350 J /kg k
ΔT = 30 - 25
= 5 °C
Putting the values in the expression above
Q = 300 x 3350 x 5
= 5025000 J
Rate at which energy is absorbed = 1200 J /s
Time required
= 5025000 / 1200
= 4187.5 S
= 69.8 minute
= 1 hour 9.8 mimutes.
