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2 years ago

Tell how electromagnetic waves differ from mechanical waves

1 answer:

3 0

Electromagnetic and mechanical waves differ in that electromagnetic waves are always longitudinal and do not require a known medium, while mechanical waves are either longitudinal or compression waves and require a medium. All known electromagnetic waves are also known as forms of light.

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A 2 kg object traveling at 5 m s on a frictionless horizontal surface collides head-on with and sticks to a 3 kg object initiall

Svetlanka [38]

Answer: (d)

Explanation:

Given

Mass of object $m=2\ kg$

Speed of object $u=5\ m/s$

Mass of object at rest $M=3\ kg$

Suppose after collision, speed is v

conserving momentum

$\Rightarrow mu+0=(m+M)v\\\\\Rightarrow v=\dfrac{2\times 5}{2+3}\\\\\Rightarrow v=2\ m/s$

Initial kinetic energy

$k_1=\dfrac{1}{2}\times 2\times 5^2\\\\k_1=25\ J$

Final kinetic energy

$k_2=\dfrac{1}{2}\times (2+3)\times 2^2\\\\k_2=10\ J$

So, it is clear there is decrease in kinetic energy . Thus, energy decreases and velocity becomes 2 m/s.

4 0

2 years ago

Plz answer fast the question

alexgriva [62]

Answer:

Angle of incidence = 20°

Angle of reflection = 20°

Explanation:

Applying,

The first Law of Refraction: The incident ray, the reflected ray and the normal at the point of incidence all lies in the plane.

From the diagram,

Angle of incidence = 90-70

Angle of incidence = 20°

From the law of reflection,

Angle of incidence = Angle of reflection

Therefore,

Angle of reflection = 20°

3 0

2 years ago

A car starts from rest and accelerates uniformly over a time of 18 seconds for a distance of 390 m. Determine the acceleration o

Sergeeva-Olga [200]

Answer:

$a=2.4\ m/s^2$

Explanation:

Given that,

The initial speed of a car, u = 0

Time, t = 18 s

Distance, d = 390 m

We need to find the acceleration of the car. Let it is a. Using the second equation of motion to find it.

$d=ut+\dfrac{1}{2}at^2$

$d=\dfrac{1}{2}at^2\\\\a=\dfrac{2d}{t^2}\\\\a=\dfrac{2\times 390}{(18)^2}\\\\a=2.4\ m/s^2$

So, the acceleration of the car is $2.4\ m/s^2$ .

5 0

2 years ago

__________ are combating competitive pressures by providing better value with private-label merchandise; adding new value-added

Neko [114]

Answer:

convinience store

Explanation:

convenience store are more like retail store providing everyday goods.

since this kind of store is usually small, maybe not as big as a department store, there is a growing number of such stores creating competitive pressures as such many are providing better value with private-label merchandise (more like re-branding or personalizing the products in the store)

8 0

3 years ago

Anna Litical analyzes the force between a planet and its moon, varying the mass of

Travka [436]

Answer:

Trial 1 is the largest, trial 3 is the smallest

Explanation:

Given:

Trial 1

M₁ = 6·10²² kg

d₁ = 3 500 km = 3.5·10⁶ м

Trial 2

M₂ = 6·10²² kg

d₂ = 7 000 km = 7·10⁶ м

Trial 3

M₃ = 3·10²² kg

d₃ = 7 000 km = 7·10⁶ м

___________

F - ?

Gravitational force:

F₁ = G·m·M₁ / d₁² = m·6.67·10⁻¹¹·6·10²² / (3.5·10⁶)² = 0.37·m (N)

F₂ = G·m·M₂ / d₂² = m·6.67·10⁻¹¹·6·10²² / (7·10⁶)² = 0.08·m (N)

F₃ = G·m·M₃ / d₃² = m·6.67·10⁻¹¹·3·10²² / (7·10⁶)² = 0.04·m (N)

Trial 1 is the largest, trial 3 is the smallest

5 0

8 months ago