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3 years ago

Quentin made a table to summarize uses of electromagnetic waves.

Physics

2 answers:

snow_lady [41]3 years ago

8 0

B luggage inspections

Dima020 [189]3 years ago

7 0

Answer: The correct answer is B

Explanation: luggage inspections Hope this helps!

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What, roughly, is the percent uncertainty in the volume of a spherical beach ball whose radius is 5.66 0.09 m?

iren2701 [21]

Answer:

4.77 %

Explanation:

We know that the volume V for a sphere of radius r is

$V(r) = \frac{4}{3} \ \pi \ r^3$

If we got an uncertainty $\Delta r$ the formula for the uncertainty of V is:

$\Delta V(r) = \sqrt{ (\frac{dV}{dr} \Delta r)^2 }$

We can calculate this uncertainty, first we obtain the derivative:

$\frac{dV}{dr} = 3 * \frac{4}{3} \ \pi \ r^2$

$\frac{dV}{dr} = 4 \ \pi \ r^2$

And using it in the formula:

$\Delta V(r) = \sqrt{ (4 \ \pi \ r^2\Delta r)^2 }$

$\Delta V(r) = \sqrt{ 4^2 \ \pi^2 \ r^4 \Delta r^2 }$

$\Delta V(r) = 4 \ \pi \ r^2 \Delta r$

The relative uncertainty is:

$\frac{\Delta V(r)}{V(r)}$

$\frac{ 4 \ \pi \ r^2 \Delta r }{ \frac{4}{3} \ \pi \ r^3}$

$\frac{ 3 \Delta r }{ r}$

Using the values for the problem:

$\frac{ 3 * 0.09 m }{ 5.66 m} = 0.0477$

This is, a percent uncertainty of 4.77 %

4 0

3 years ago

Of the three forces acting on the rock as it slides down the bowl, which (if any) are constant and which are not? explain.

choli [55]

Answer

Hi,

The forces are; weight (gravity), Normal/centripetal force and friction. Force due to gravity is constant where as friction and centripetal are not.

Explanation

Weight is constant, given by the force of gravity on the object. The centripetal force is a function of the angles occurring between the velocity vector and the weight vector that is at right angle with the perpendicular line drawn from the surface. Friction is a function of the centripetal force thus it also varies.

Hope this helps!

6 0

3 years ago

If a ball speeds up as it is rolling down a hill, the forces acting on it must be -

VMariaS [17]

Answer:

the forces acting on it must be strong because gravity is pushing the ball down

Explanation:

3 0

3 years ago

Can a body have zero velocity and finite acceleration?Explain

sergejj [24]

Answer:

Kinda? Depends what the question is fully asking

Explanation:

Acceleration is a change in velocity. So I guess if the velocity of something is -2 m/s and its positively accelerating at a value of +1 m/s, then that means every second its velocity changes by +1m/s.

So that -2 m/s thing after one second will be going -1 m/s.

After another second it'll be going 0 m/s.

After another itll be going +1 m/s and so on.

So at one point for a brief moment, it can have an acceleration but be at 0 m/s velocity.

5 0

3 years ago

James gently releases a ball at the top of a slope But does not push the ball. Space the ball rolls down the slope. Which force

NARA [144]

On an incline, the force causing the ball to move downwards would be gravity. Additionally, the component of gravity causing this ball to move downwards would be mgsintheta.

Hope this helps!

7 0

3 years ago

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