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3 years ago

What sort of waves exhibit the doppler effect?

Physics

1 answer:

Alexus [3.1K]3 years ago

7 0

The waves that occur when you drop and stone into the water when skipping rocks

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Do all metals stick to magnets? Give an example. I NEED HELP FASTT

ludmilkaskok [199]

Answer:

Explanation:

Not all metals stick to magnets. Like aluminum. if you were to stick a magnet on to an aluminum it would fall off.

6 0

2 years ago

An airplane of mass 1.60 ✕ 104 kg is moving at 66.0 m/s. The pilot then increases the engine's thrust to 7.70 ✕ 104 N. The resis

Ivan

(a) No, because the mechanical energy is not conserved

Explanation:

The work-energy theorem states that the work done by the engine on the airplane is equal to the gain in kinetic energy of the plane:

$W=\Delta K$ (1)

However, this theorem is only valid if there are no non-conservative forces acting on the plane. However, in this case there is air resistance acting on the plane: this means that the work-energy theorem is no longer valid, because the mechanical energy is not conserved.

Therefore, eq. (1) can be rewritten as

$W=\Delta K + E_{lost}$

which means that the work done by the engine (W) is used partially to increase the kinetic energy of the airplane ( $\Delta K$ ) and part is lost because of the air resistance ( $E_{lost}$ ).

(b) 77.8 m/s

First of all, we need to calculate the net force acting on the plane, which is equal to the difference between the thrust force and the air resistance:

$F=7.70\cdot 10^4 N - 5.00 \cdot 10^4 N=2.70\cdot 10^4 N$

Now we can calculate the acceleration of the plane, by using Newton's second law:

$a=\frac{F}{m}=\frac{2.70\cdot 10^4 N}{1.60\cdot 10^4 kg}=1.69 m/s^2$

where m is the mass of the plane.

Finally, we can calculate the final speed of the plane by using the equation:

$v^2- u^2 = 2aS$

where

$v=?$ is the final velocity

$u=66.0 m/s$ is the initial velocity

$a=1.69 m/s^2$ is the acceleration

$S=5.00 \cdot 10^2 m$ is the distance travelled

Solving for v, we find

$v=\sqrt{u^2+2aS}=\sqrt{(66.0 m/s)^2+2(1.69 m/s^2)(5.00\cdot 10^2 m)}=77.8 m/s$

8 0

3 years ago

Two men decide to use their cars to pull a

Ulleksa [173]

The resultant force in the direction the truck is headed is:

734N*cos(31) + 1084N*cos(23)
629N+998N = 1627N

7 0

3 years ago

A box has a mass of 35kg.he pulls the rope horizontally with a force of 175 N. Find the horizontal acceleration of the box as it

Cloud [144]

Answer:

3.43 m/s^2

Explanation:

Force is equal to mass times acceleration. (F=ma). You can use inverse operations to get the formula for acceleration, which is acceleration is equal to force divided by mass. (a=F/m). Since there are two forces here, the force friction (55 N), and the force applied (175 N), we must solve for the net force. To solve for the net force, you take the applied force (175 N) and subtract the frictional force from it (55 N). Thus, the net force is 120 N. With this done, we can now solve for our acceleration.

Using the equation for acceleration, we take the force and divide it by mass.

120/35

Answer: 3.43* m/s^2**

*Note: This is rounded to the nearest hundredth, the full answer is: 3.42857143

**Note: In case you're confused, this is meters per second squared.

8 0

3 years ago

What force is required to cause a 5 kg bowling ball to accelerate at 4 m/s2

Scorpion4ik [409]

Answer:

20 N

Explanation:

By Newton's 2nd law,

The rate of change of momentum is directly proportional to the unbalance force applied on the object,

By that you can get the equation,

F = ma

= 5 × 4 = 20 N

4 0

3 years ago