Which of the following statements is incorrect?

1) A ray of light travels from a point A to point B in a path that takes the shortest time

2) In reflection angle of incidence equal to angle of reflection

3) Magnification for a plane mirror is always unity

4) A plane mirror can form only virtual images

Answer:

Thermal capacity of the object = 720 j/°C

Explanation:

Given:

Specific heat capacity of metal = 360J/(kg°C)

Mass of given object = 2 kg

Find:

Thermal capacity of the object

Computation:

Thermal capacity = Specific heat x Mass

Thermal capacity of the object = Specific heat capacity of metal x Mass of given object

Thermal capacity of the object = 360 x 2

Thermal capacity of the object = 720 j/°C

Answer:

The heat produced in the longer wire is 200 J.

Explanation:

When the two wires are connected in parallel then the voltage across both the wires is same.

Let the length of the second wire is L and the radius of the second wire is R.

The length of the first ire is 2L and the radius of the first wire is 2R.

Heat produced in the second wire is 100 J.

Let the heat produced in the first wire is H'.

The resistance of the wire is proportional to length of the wire and inversely proportional to the area of the wire.

[tex]\frac{R_2}{R_1}=\frac{L\times \pi\times 4R^2}{2L\times \pi\times R^2}\\\\\frac{R_2}{R_1}=2[/tex]

The heat produced is given by

[tex]H=\frac{V^2}{R}\\\\\frac{H_1}{H_2}=\frac{R_2}{R_1}\\\\\frac{H_1}{100}=2\\\\H_1=200 J[/tex]

By Newton's second law, the net force acting on the crate parallel to the surface is

∑ F = mg sin(10°) - 800 N = ma

where m = 500 kg is the mass of the crate and a is the acceleration.

Solve for a :

a = ((500 kg) (9.80 m/s^2) sin(10°) - 800 N) / (500 kg)

a ≈ 0.102 m/s^2

Answer:

33.33j+6.67i km/hr

Explanation:

From the law of conservation of momentum,

Applying,

mu+m'u' = V(m+m')............... Equation 1

Where m = mass of the truck, m' = mass of the car, u = initial velocity of the truck, u' = initial velocity of the car, V = Final velocity.

Note: let j represent the north, and i  represent the east

From the question,

Given: m = 1500 kg, u = 60j, m' = 1200 kg, u' = 15i

Substitute these values into equation 1

1500*60j+1200*15i = V(1500+1200)

90000j+18000i = 2700V

V = (90000j+18000i)/2700

V = 33.33j+6.67i km/hr

Answer:

One end of any bar magnet will always want to point north if it is freely suspended. This is called the north-seeking pole of the magnet, or simply the north pole. The opposite end is called the south pole.

Explanation:

Answer:

North Pole and South Poles

Explanation:

There is no east or west in a magnetic field of a magnet. The magnetic field lines comes from North pole to south pole.

Answer:

total distance dibide by total time

Answer:

here is your answer

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Answer:

152,155 J

Explanation:

115,333 + 36,822 = 152,155J

Answer:

the work done by the woman is 6,000 J

Explanation:

Given;

force applied by the woman, F = 400 N

distance moved by the woman, d = 15 m

The work done by the woman is calculated as follows;

W = F x d

W = 400 N x 15 m

W = 6000 Nm = 6,000 J

Therefore, the work done by the woman is 6,000 J

Answer:

table and chair

Explanation:

In a meeting room there are tables, chairs, and other people. Which of them have temperatures

a) smaller, b) bigger and d) equal to that of air?

the temperature of tables and chairs is same as air.

Answer:

0.6 resistance

Answer:

The iron bolt is attracted to the electromagnet. The force of attraction between the electromagnet's core and the iron bolt is greater than the force of the spring, so the iron bolt is pulled out of its housing in the door

Explanation:

Answer:

it helps me

Explanation:

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Answer:

In a circular motion, the object just moves in a circle. In rotational motion, the object rotates about an axis. ... For example, Earth rotating on its own axis.

Answer:

Its different

Explanation:

it's different because

Answer:

Kayla. You can calculate it using the formula for momentum: momentum=mass×velocity and find the bigger number between the two momentums

Answer:

E

Explanation:

it has more mass

The medium in which mechanical waves will travel the slowest in is air which is gaseous medium.

A mechanical wave is a type of wave that requires material medium for its propagation.

An example of mechanical wave is sound wave because sound wave requires material medium for its propagation.

Sound waves travel fastest in solid, followed by liquid, then least in gasous medium.

Thus, the medium in which mechanical waves will travel the slowest in is air which is gaseous medium.

Learn more about mechanical waves here: https://brainly.com/question/9242091

Answer:

1 is false 2 is true 3 is false

Answer:

Gravitational force -an attractive force that exists between all objects with mass; an object with mass attracts another object with mass; the magnitude of the force is directly proportional to the masses of the two objects and inversely proportional to the square of the distance between the two objects.

Explanation:

hope it helped

hope this helps

Answer:

If a person is pushing a desk across the room, then there is an applied force acting upon the object. The applied force is the force exerted on the desk by the person.

Answer:

Yes. The area around you would be a bit red I think.

Explanation:

[tex]C.) \: Conduction \: \\ \\ = > it \: is \: a \: process \: of \: transferring \: \\ \\ of \: heat \: from \: one \: object \: to \: another \\ \\ when \: they \: are \: in \: contact \: [/tex]

By the conduction process the heat reaches the pin.Option C is correct.

The term "heat transfer" refers to the movement of heat. The flow of heat across a system's boundary is due to a temperature differential between the system and its surroundings.

Conduction is the type of heat transfer occurs mainly in solid or by contact.In the given condition the rod is then heated continuously at one end and the pins fall off in the order 4, 3, 2, 1​.

By the conduction process the heat reaches the pin.

Hence option C is correct.

To learn more about the heat transfer refer to the link;

https://brainly.com/question/13433948

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Answer:

i) v = 1.47 cm/s

ii) distance = 219.8 cm

iii) displacement = 28cm

Explanation:

Remember that:

The motion of the tip of the second hand is a circular motion.

For something that rotates with an angular frequency ω, and a radius R, the velocity is given by:

v = ω*R.

i) We know that the second hand of a clock does a complete rotation each 60 seconds.

Then the period is:

T = 60s

And the frequency is the inverse of the period, so:

f = 1/T

f = (1/60s)

And the angular frequency is 2*pi times the normal frequency, thus:

ω = 2*pi*f

ω = 2*pi*(1/60s)  = (2*pi/60s)

And the radius will be 14 cm, the velocity of the ant is:

v = (2*pi/60s)*14cm

if we replace pi by 3.14 we get:

v =  (2*3.14/60s)*14cm = 1.47 cm/s

ii) The distance covered by the ant in 150 seconds:

Remember that the period of the clock is T = 60s

so in 150 seconds we have:

150s/60s = 2.5 revolutions.

Then the total distance covered is 2.5 times the perimeter of a circle of radius R = 14cm, this is:

distance = (2.5)*2*pi*14cm

              = (2.5)*2*3.14*14cm = 219.8 cm

iii) We want to know the displacement, this is, the difference between the final position and the initial position.

In 150 seconds, the ant does 2.5 revolutions.

So the ant will end in the opposite side of the circle where she started (if the ant started when the second hand was at the "3", then the final position is when the second hand is at the "9").

So the displacement will be equal to twice the radius, or the diameter of the circle.

if the radius is 14cm, the diameter is:

2*14cm = 28cm

the displacement is 28cm

Explanation:

Glass is the best sound absorber material.