What is the main way in which heat transfer occurs in liquids and gases?

Which is NOT an example of unbalanced forces acting on an object

grin007 [14]

Answer:

C. a motorcycle changing speed from 20km/h to 35km/h

Explanation:

The choice not showing unbalanced forces acting on the object is a motorcycle changing speed from 20km/h to 35km/h.

This change in velocity shows that the body is accelerating during the time interval.

When a body is accelerating, it is changing it's motion and this implies that some unbalanced forces are acting in the body. Unbalanced body changes the state of motion of a body from rest to acceleration or deceleration as the case may be.

5 0

3 years ago

If the releases 39.4 kj of energy, how many kilocalories does it release? (1 cal = 4.184 j) (round off answer to 2 decimal place

REY [17]

By using unit conversion, the energy released in kilocalories is 9.42 kcal.

We need to know about unit conversion to solve this problem. There are several energy units which able to explain how much the energy is such as calories and joule. The energy unit can be converted to another unit by unit conversion. The unit conversion of calorie to joule is

1 cal = 4.184 joule

From the question above, we know that

E = 39.4 kJ

By using the unit conversion, we can convert the energy into calorie

E = 39.4 kJ

E = 39.4 x 10³ J

E = 39.4 x 10³ / 4.184 cal

E = 9.42 x 10³ cal

E = 9.42 x 10³ /10³ kcal

E = 9.42 kcal

Hence, the energy released in kilocalories is 9.42 kcal.

Find more on unit conversion at: brainly.com/question/141163

#SPJ4

8 0

2 years ago

What is the magnitude of the momentum of a 11kg object moving at 2.2 m/s?

tangare [24]

Answer:

<h3>The answer is 24.2 kgm/s</h3>

Explanation:

The momentum of an object can be found by using the formula

<h3>momentum = mass × velocity</h3>

From the question

mass = 11 kg

velocity = 2.2 m/s

We have

momentum = 11 × 2.2

We have the final answer as

Hope this helps you

4 0

3 years ago

How much heat is needed to raise the temperature of 9g of water by 17oC?

andre [41]

Well the heat that is needed to raise the temperature of 10g of water by 17oC is 7

6 0

3 years ago

A 1.65 kg mass stretches a vertical spring 0.260 m If the spring is stretched an additional 0.130 m and released, how long does

Irina-Kira [14]

Answer:

The system will take approximately 0.255 seconds to reach the (new) equilibrium position.

Explanation:

We notice that block-spring system depicts a Simple Harmonic Motion, whose equation of motion is:

$y(t) = A\cdot \cos \left(\sqrt{\frac{k}{m} }\cdot t +\phi\right)$ (1)

Where:

$y(t)$ - Position of the mass as a function of time, measured in meters.

$A$ - Amplitude, measured in meters.

$k$ - Spring constant, measured in newtons per meter.

$m$ - Mass of the block, measured in kilograms.

$t$ - Time, measured in seconds.

$\phi$ - Phase, measured in radians.

The spring is now calculated by Hooke's Law, that is:

$k = \frac{m\cdot g}{\Delta y}$ (2)

Where:

$g$ - Gravitational acceleration, measured in meters per square second.

$\Delta y$ - Deformation of the spring due to gravity, measured in meters.

If we know that $m=1.65\,kg$ , $g = 9.807\,\frac{m}{s^{2}}$ and $\Delta y = 0.260\,m$ , then the spring constant is:

$k = \frac{(1.65\,kg)\cdot \left(9.807\,\frac{m}{s^{2}} \right)}{0.260\,m}$

$k = 62.237\,\frac{N}{m}$

If we know that $A = 0.130\,m$ , $k = 62.237\,\frac{N}{m}$ , $m=1.65\,kg$ , $x(t) = 0\,m$ and $\phi = 0\,rad$ , then (1) is reduced into this form:

$0.130\cdot \cos (6.142\cdot t)=0$ (1)

And now we solve for $t$ . Given that cosine is a periodic function, we are only interested in the least value of $t$ such that mass reaches equilibrium position. Then:

$\cos (6.142\cdot t) = 0$

$6.142\cdot t = \cos^{-1} 0$

$t = \frac{1}{6.142}\cdot \left(\frac{\pi}{2} \right)\,s$

$t \approx 0.255\,s$

The system will take approximately 0.255 seconds to reach the (new) equilibrium position.

4 0

3 years ago