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3 years ago

Which statement correctly describes both sound and light waves?

Physics

1 answer:

olga55 [171]3 years ago

6 0

Answer:

Option C. Light waves can travel through space, sound waves cannot.

Explanation:

Light is an electromagnetic wave which requires no Meduim for propagation. However, sound wave requires a medium for propagation. Since space is empty, sound can not travel through it.

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What Is the volume of the rectangular prism of 6cm 9cm and 5cm

Crazy boy [7]

Volume is length times width times height, so 6 times 9 times 5 is 270 centimeters.

8 0

3 years ago

An object 82 cm high forms a virtual image 4.1 cm high located 4.6 cm behind a mirror. Find the object distance.

ioda

Answer:

The object distance is 92 cm.

Explanation:

let v be the image distance and h be the height of the image, let u the be the object distance and H be the height of the object.

then, the magification of the mirror is given by:

m = -v/u and m = h/H

so, -v/u = h/H

u = -v×H/h

= -(-4.6)×(82)/(4.1)

= 92 cm

Therefore, the object distance is 92 cm.

8 0

3 years ago

"She finished the sprint with the speed of a cheetah." This statement represents which of the

Naily [24]

Answer:

Poetic

Explanation:

I took the test

8 0

3 years ago

A gardener pushes a 20 kg lawnmower whose handle is tilted up 37∘ above horizontal. The lawnmower's coefficient of rolling frict

e-lub [12.9K]

Answer:

58.4 W

Explanation:

The speed of the lawnmower is constant: this means that its acceleration is zero, so the net force on it is zero.

The equation of the forces along the two directions therefore are:

- Perpendicular to the floor: $F sin \theta + R -mg =0$

- Parallel to the floor: $F cos \theta - \mu R = 0$

where

F is the push of the gardener

R is the normal reaction

m = 20 kg is the mass

g = 9.8 m/s^2 is the acceleration of gravity

$\mu=0.18$ is the coefficient of friction

$\theta=37^{\circ}$

Solving for R,

$R=mg-Fsin \theta$

Substituting into the other equation,

$F cos \theta - \mu (mg-Fsin \theta) = 0\\F cos \theta - \mu mg + \mu F sin \theta = 0\\F(cos \theta+\mu sin \theta)=\mu mg\\F=\frac{\mu mg}{cos \theta + \mu sin \theta}=\frac{(0.18)(20)(9.8)}{cos 37^{\circ}+0.18(sin 37^{\circ})}=38.9 N$

And the power he must supply therefore is the product of this force and the speed:

$P=Fv=(38.9)(1.5)=58.4 W$

7 0

4 years ago

A raindrop of mass 2.52 × 10-5 kg falls vertically at constant speed under the influence of gravity and air resistance. Model th

goldfiish [28.3K]

Answer:

0.0247212 Joules

-0.0247212 Joules

Explanation:

Potential energy

$PE=mgh\\\Rightarrow PE=2.52\times 10^{-5}\times 9.81\times 100\\\Rightarrow PE=0.0247212\ Joules$

a) The work done by the gravitational force is given by the potential energy that the body has at the start of the fall.

Work done is considered as positive if the force which is being applied is in the direction of motion.

Hence, the work done on the raindrop by the gravitational force is 0.0247212 Joules

b) As the drop is falling the air resistance provides an opposite force this means the sign of the work done will be negative.

So, the work done on the raindrop by air resistance is -0.0247212 Joules

5 0

3 years ago