Need help really fast ! can give brainliest if correct :> thanks <3

So long as there are(is) ______ there is no movement.

patriot [66]

Answer:

answer is friction. MCQ A is answer

6 0

2 years ago

Design an experiment to test the rate at which temperature changes for two different masses (amounts) of water.

mrs_skeptik [129]

Answer:Experimental Question: How does the amount of a substance affect the rate at which temperature changes?

It depends on the conductivity of the material. If the shift is extreme, the temperature near the heating / cooling source will be similar to the temperature of the heating / cooling source and it will take time for the remainder of the material to rise to temperature. It will depend on the conductivity of the material.

Hypothes is:

Materials List:

• digital stopwatch

• 250ml beaker

• rubber bung

• thermometer

• bunsen burner

• tripod

• gauze

• retort stand and clamp

• goggles

Safety Procedures *:

1. Adult supervision is required.

2. Wear safety goggles, apron, and closed-toe shoes.

3. Do not wear baggy sleeves or dangling jewelry. Tie long hair back.

4. Use hot pads or oven mitts to handle hot objects.

5. Do not reach over a hot burner.

6. Do not leave the experiment unattended.

7. Clean up spills immediately.

8. Report any injuries to your Learning Coach or adult supervisor immediately

Experimental Procedures :

• Fill an empty beaker with exactly 150ml of water (check side-scale of beaker)

• Set up apparatus as shown above. Ensure the thermometer is about 2cm above the bottom of the beaker.

• Light the bunsen burner and put on a blue flame. Heat up the water.

• When the temperature on the thermometer has reached 90°C, immediately switch off the burner.

• Start the stopwatch and time for 5.0 minutes.

• Read the thermometer value at the 5.0 minute mark.

• Before repeating the experiment, check the level of water is still 150ml

Data Table:

Start Temperature of Water (°C) Temperature after 5min (°C) Drop in Temperature

(°C) Average Rate of Cooling x 1000 (°C/s)

80 70 10 17

75 66 9 15

70 62 8 13

65 59 6 10

60 55 5 8

Analysis:

Conclusions : There is a strong correlation between the average rate of cooling and the start temperature: the greater the start temperature, the faster the average rate of cooling.

Explanation:

use quillbot or this will be considered plagerism

3 0

3 years ago

What is the solution to the problem expressed to the correct number of significant figures?

oksian1 [2.3K]

Answer:

73.72

Explanation:

For this subtraction problem, the answer or solution is expressed to the least precise of the numbers we are trying to subtract.

The least precise number is the number with the lowest significant numbers:

105.4 - 31.681

105.4 has 4 significant numbers

31.681 has 5 significant numbers

So;

105.4

- 31.681

------------------

73.719

----------------

The solution is therefore 73.72

7 0

3 years ago

You stand17.5 m from a wall holding a baseball. You throw the baseball at the wall at an angle of 20.5∘ from the ground with an

Lelechka [254]

Answer: 8.8 m

Explanation:

The movement of the baseball to the wall is a example of parabolic motion. While the baseball aproach the wall it is affected by gravity.

In this case, because the Initial Velocity of the ball is a vecotr, it can be defined using its two directionals compounds. One, on the Y-axis and another on the X-axis. This can be related, on how a hypotenuse is the product of two legs of the triangle. Because of this, each one of this, can be know using the following equation:

Vx = Vo * cos(∅)

Vy = Vo * sin(∅)

Where Vo is the initial velocity 27.5 m/s, and ∅ is the angle which is 20.5°. So we calculate:

Vx = 27.5m/s * cos(20.5)

Vx = 27.5m/s * 0.936

Vx = 25.74m/s

Vy = 27.5m/s * sin(20.5)

Vy = 9.62m/s

Now the movement is divided on two parts, one under the effect of gravity and another one with a constant velocity.

To know how tall does the baseball hit the wall, we need to know first how much time it takes the ball to reach the wall on the X-axis. The wall is 17.5m away, we velocity on Vx that is constant we can calculate as it follow:

Time (T) = Distance (D) / Velocity (V)

Where Distance is 17.5m and our Velocity is the Vx calculated before.

T = 17.5 m / 25.74m/s

T = 0.68s

This is the time it takes the ball to reach the wall.

Know with the time, we can calculate the how tall it got on that time with the following equation:

$x = (Vo*t) + (\frac{1}{2} *a*t^{2} )$

Where Vo is the Y-Compound of the Initial Velocity.

a is the aceleration, in this case the Gravity. Which, will be negative because is oposing the movement. Gravity is equal to 9.81 $m/s^{2}$

And t is the time it takes the ball to get to the wall.

$x = (Vy*T) + (\frac{1}{2} *g*T^{2} )$

$x = ((9.62m/s)*0.68s) + (\frac{1}{2} *(9.81m/s^{2})*(0.68s)^{2} )$

$x = 8.8 m$

This is the height that the baseball touch the wall.

6 0

3 years ago

A proton is released from rest at the origin in a uniform electric field in the positive x direction with magnitude 850 N/C. Wha

Gwar [14]

A proton is released from rest at the origin in a uniform electric field in the positive x direction with magnitude 850 N/C. The change in the electric potential energy of the proton-field system when the proton travels to x = 2.50m is -3.40 × 10⁻¹⁶ J (Option B)

<h3 /><h3>How is the change in electric potential energy of the proton-field system calculated?</h3>

Work done on the proton =Negative of the change in the electric potential energy of the proton field
In the given case, W = -qΔV
-W = qΔV
= qEcosθ
Therefore, work done on the proton = -e(8.50× $10^2$ N/C)(2.5m)(1)
= -3.40× $10^-^1^6$ J
Any change in the potential energy indicates the work done by the proton.
Therefore the positive sign shows that the potential energy increases when the proton does the work.
The negative sign shows that the potential energy decreases when the proton does the work.

To learn more about electric potential energy, refer

brainly.com/question/14306881

#SPJ4

3 0

2 years ago