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3 years ago

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Physics

1 answer:

vichka [17]3 years ago

4 0

Answer:

The correct options here are C and D

Explanation:

DC here means "direct current". Direct current is characterized by it's flow of current been unidirectional (meaning it's current flows in just one direction). Thus, to get the answer to the question one must look for options that only move in a single direction. Options A and B move in a back and forth direction meaning they are not unidirectional.

A longitudinal wave moves in the same direction OR opposite direction to the direction of the propagating wave. This means longitudinal wave is also unidirectional. Option C is correct.

1st graders, in a line, going to the cafeteria also move in one direction (direction of the cafeteria). Thus, option D is also correct.

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In the aerials competition in skiing, the competitors speed down a ramp that slopes sharply upward at the end. the sharp upward

ladessa [460]

Answer:

The skier’s launch speed = 17.08 m/s

Explanation:

The motion of skiing is projectile motion.

Projectile motion has two types of motion Horizontal and Vertical motion.

Vertical motion:

We have equation of motion, v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration and t is the time taken.

Considering upward vertical motion of projectile.

In this case, Initial velocity = vertical component of velocity = u sin θ, acceleration = acceleration due to gravity = -g $m/s^2$ and final velocity = 0 m/s.

0 = u sin θ - gt

t = u sin θ/g

Total time for vertical motion is two times time taken for upward vertical motion of projectile.

So total travel time of projectile = 2u sin θ/g

Horizontal motion:

We have equation of motion , $s= ut+\frac{1}{2} at^2$ , s is the displacement, u is the initial velocity, a is the acceleration and t is the time.

In this case Initial velocity = horizontal component of velocity = u cos θ, acceleration = 0 $m/s^2$ and time taken = 2u sin θ /g

So range of projectile, $R=ucos\theta*\frac{2u sin\theta}{g} = \frac{u^2sin2\theta}{g}$

Vertical motion (Maximum height reached, H) :

We have equation of motion, $v^2=u^2+2as$ , where u is the initial velocity, v is the final velocity, s is the displacement and a is the acceleration.

Initial velocity = vertical component of velocity = u sin θ, acceleration = -g, final velocity = 0 m/s at maximum height H

$0^2=(usin\theta) ^2-2gH\\ \\ H=\frac{u^2sin^2\theta}{2g}$

We have θ = 63° and H = 11.8 meter.

Substituting

$11.8=\frac{u^2sin^263}{2*9.81}\\ \\ u^2=\frac{11.8*2*9.81}{sin^263}=\frac{231.516}{0.794} =291.58\\ \\ u=17.08m/s$

The skier’s launch speed = 17.08 m/s

3 0

4 years ago

Read 2 more answers

Sunlight strikes a solar panel.which is then used to power the lights in the house. What are the energy transformation taking pl

AVprozaik [17]

Answer:Thermal energy to electric energy to light energy

6 0

4 years ago

A truck traveling at a constant speed of 24 m/s passes a more slowly moving car. The instant the truck passes the car, the car b

Ymorist [56]

Answer:

7.15 m/s

Explanation:

We use a frame of reference in which the origin is at the point where the trucck passed the car and that moment is t=0. The X axis of the frame of reference is in the direction the vehicles move.

The truck moves at constant speed, we can use the equation for position under constant speed:

Xt = X0 + v*t

The car is accelerating with constant acceleration, we can use this equation

Xc = X0 + V0*t + 1/2*a*t^2

We know that both vehicles will meet again at x = 578

Replacing this in the equation of the truck:

578 = 24 * t

We get the time when the car passes the truck

t = 578 / 24 = 24.08 s

Before replacing the values on the car equation, we rearrange it:

Xc = X0 + V0*t + 1/2*a*t^2

V0*t = Xc - 1/2*a*t^2

V0 = (Xc - 1/2*a*t^2)/t

Now we replace

V0 = (578 - 1/2*1.4*24.08^2) / 24.08 = 7.15 m/s

6 0

3 years ago

Explain why gases are more compressible than solid

Oduvanchick [21]

Answer:

If we put pressure on a solid or a liquid, there is essentially no change in volume. ... The kinetic-molecular theory explains why gases are more compressible than either liquids or solids. Gases are compressible because most of the volume of a gas is composed of the large amounts of empty space between the gas particles.

Explanation:

7 0

3 years ago

How are different types of energy used?

Luda [366]

Answer:

The 6 Forms of Energy. There are many forms of energy: like solar, wind, wave and thermal to name a few, but the 6 Forms of Energy we study in Needham are: Sound, Chemical, Radiant, Electric, Atomic and Mechanical. Sound Energy- is produced when an object is made to vibrate.

Explanation:

4 0

3 years ago