Intro physics course is beginning to move into 2D kinematics, stuck on the first real question.A stone is thrown horizontally at 15m/s from the top of a cliff 44m high. What is the velocity of the rock after 2 seconds?
I tried 3(-9.8m/s2) and some other formula's but could never arrive at the correct answer of 24.7m/s. Could someone explain how to arrive at this answer and the reasoning behind it?

Answers

Answer 1
Answer:
-- You kick it horizontally, out off of the cliff, at 15 m/s.  There's no horizontal
force on it, so its horizontal speed never changes.

-- As soon as it clears the edge of the cliff, gravity starts accelerating it
downward, 9.8 m/s faster every second.  After 2 seconds, it has

                           (2 x 9.8) = 19.6 m/s

of downward vertical speed.

At this point, its velocity points somewhere between horizontal and downward-
vertical.  I gather from the wording of the question that you're not so much
concerned with the direction of the velocity as you are with its magnitude ...
that is, the stone's speed in whatever direction it's actually moving.

You have a vector with two components:  15 horizontal and 19.6 vertical.
Those components are perpendicular, so their resultant is just the hypotenuse
of the right triangle.

             (Speed)² = (15 m/s)² + (19.6 m/s)²

                           = (225 m²/s²) + (384.16 m²/s²)

                           =      (609.16 m²/s²) .

             Speed  =  √(609.16 m²/s²)  =  24.681 m/s 

That's where the 24.7 m/s comes from.    /\

(I just looked back at the question again.  Notice that we don't care
how high the cliff is.  That "44m" is in there only to distract those who
don't know what they're doing, and who think that they must use it
just because it's there.)


Answer 2
Answer: ok so the x velocity is 15 m/s with no acceleration
the y velocity is 19.62 after 2 seconds because of acceleration of 9.81 m/s x 2

the velocity can be found by making a diagram and solving through the pythagorean theorem

15 sq + 19.62 sq = velocity sq
225 + 384.9444 = velocity sq
velocity = sqrt 609.944 
velocity = 24.7

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You are asked to measure the density of a cube that has a side of 10 centimeters, and weighs 1 kg nominally. The tools you have are a ruler with the smallest reading at 1 mm, and a scale with a precision down to 0.1 g. Both tools are calibrated. Please estimate the final error on the density of the object that you measure. ​

Answers

Answer:

To estimate the final error on the density of the cube, we can consider the errors introduced by both the measurement of its volume and its weight.

1. Volume Measurement:

- The side length of the cube is given as 10 centimeters, and your ruler can measure to 1 mm accuracy.

- So, the error in measuring the side length is ±0.05 cm (half of the smallest measurement unit).

- To calculate volume, you need to cube the side length: Volume = (10 cm)^3 = 1000 cm^3.

- Using the error propagation rule, the relative error in volume is ±0.05 cm / 10 cm = ±0.005.

2. Weight Measurement:

- The weight is given as 1 kg nominally, which is equivalent to 1000 g.

- Your scale has a precision down to 0.1 g.

- So, the error in measuring the weight is ±0.1 g / 1000 g = ±0.0001 (0.01%) relative error.

Now, to calculate the final error in density, you need to consider both errors in volume and weight:

Density = Weight / Volume

Relative Error in Density = (Relative Error in Weight) + (Relative Error in Volume)

Relative Error in Density = (0.0001) + (0.005) = 0.0051 or 0.51%

So, the final estimated error on the density of the cube is approximately ±0.0051 g/cm^3 or ±0.51%.

Final answer:

The density of the cube is calculated using its mass and volume, with potential errors from the measurements of these quantities leading to a total estimated density error of approximately ±3.01%.

Explanation:

The density of an object is given by the formula density = mass/volume. In this case, the mass of the cube is given as 1 kg (or 1000 g for consistency with the scale's precision), and the volume of the cube can be calculated from the given side length using the formula for the volume of a cube, volume = side³, which equals 1000 cm³.

However, there are measurement errors associated with both the ruler and scale. The ruler can measure to the nearest mm (or 0.1 cm), so the error is ±0.1 cm on each measurement of the cube's sides, leading to a volume error of about ±3%. The scale can measure to the nearest 0.1 g, which gives a mass error of about ±0.01%. The total error in the density, obtained by summing these errors, is therefore approximately ±3.01%.

Learn more about Error Estimation here:

brainly.com/question/32513602

#SPJ2

If you wanted to increase the voltage, which would you use?a. generator
b. step-up transformer
c. step-down transformer
d. motor
e. detector

Answers

The correct answer of the question is :  B) Step-up transformer.

EXPLANATION :

Before coming into any conclusion, first we have to understand the step-up and step-down transformer.

The step-up transformer is the transformer whose transformer ratio is greater than one. It means it will increase the voltage of the source or decrease its current.

On the other hand, the transformer ratio of step-down transformer is less than one. Hence, it will decrease the higher voltage to lower voltage or increase the lower current into higher current of the given source.

As per the question, we want to increase the voltage of the source.

Hence, we have to use step-up transformer.

b) step-up transformer

Charged objects have a _________ charge. A. net B. moving C. positive D. negative

Answers

Charged objects have a Net charge.

A 6kg object has 350j of kinetic energy. find the velocity of the object?

Answers


We have no information describing the direction in which
the object is moving, so we're in no position to discuss its
velocity.   ==> We have only speed to work with.

                                      Kinetic energy = (1/2) (mass) (speed²)

                                                   (350 J) = (1/2) (6 kg) (speed²)

Divide each side by  3 kg :    (350J / 3 kg)  =  (speed²)

Take the square root of each side:       Speed  =  10.8 m/s  (rounded)


Units (for the curious/inquisitive):

[Energy] = [work] =        [force] x                [distance]

                             = [mass-distance/time²] x [distance]

                             =  [ kg-meter / sec² ]  x  [ meter ]

                             =  [ kg-meter² / sec² ]  =  Joule

Energy / mass  =  Joule/kg  =  [ meter² / sec² ]  =  (speed²)

   

Speed / 16.0 m/s 12.0- 8.0 4.0 0 0 0.5 1.0 1.5 time / seconds 2.0 2.5 3.0 calculate the distance that the car travels in the first 0.5 seconds calculate the distance that the car travels in the first 0.5 seconds ​

Answers

Answer: 8 m

Explanation:

From the equation distance = velocity * time, we can find the distance from a velocity vs. time graph by finding the area under the curve, since we get that area from multiplying velocity and time together.

For the first 0.5 seconds, the velocity is 16 m/s and the change in time is 0.5.

16 * 0.5 = 8 m.

Learn more about the relationship between distance and velocity here: brainly.com/question/29409777

You run straight off a high diving board at a speed of 6 m/sec. You hit the water 2 seconds later.a. How far did you travel horizontally during the 2 seconds?
b. How far did you travel vertically during the 2 seconds?
c. How fast were you moving horizontally when you hit the water?
d. How fast were you moving vertically when you hit the water?

Answers

My answers are in the comments. Sorry for the repeated answers on some of them