Explain why an object can’t contain heat?

A student leaving school travels 100 m East before he realizes he left his textbook in his locker. He heads back towards school,

andrew11 [14]

-- The overall distance he travels is (100m + 30m + 70m) = 200 meters.

-- His displacement when he arrives at his front door is

D = (100m East) + (30m West) + (70m East)

D = (100m + 70m)East + (30m)West

D = (170m East) + (30m West)

D = 140 meters East

It's interesting to notice that his displacement is 60 meters shorter than the distance he walked.

That's because there's a stretch of 30 meters somewhere in the middle that he actually covered three times.

Two of those times added to the distance his shoes covered (2x30m=60m), but they cancelled out of the displacement.

His front door is 140 meters East of school. He walked 60m farther than that, going back and forth over the 30m piece.

6 0

4 years ago

Which of the following is inversely proportional to the gravitational force between two masses?

Mrrafil [7]

It is D, the distance between each object squared. We get this from solving for the force of gravity, which is

F = G((m1*m2)/(r^2)).

Here, you can see that the masses of the two objects are divided by their total distance apart from each other (r) squared.

6 0

3 years ago

Dwayne ‘The Rock’ Johnson needs to escape from the fourth floor of a burning building (in a movie). He ties a rope around his wa

ZanzabumX [31]

Answer:

Final Speed of Dwayne 'The Rock' Johnson = 15.812 m/s

Explanation:

Let's start out with finding the force acting downwards because of the mass of 'The Rock':

Dwayne 'The Rock' Johnson: 118kg x 9.81m/s = 1157.58 N

Now the problem also states that the kinetic friction of the desk in this problem is 370 N

Since the pulley is smooth, the weight of Dwayne Johnson being transferred fully, and pulls the desk with a force of 1157.58 N. The frictional force of the desk is resisting this motion by a force of 370 N. Subtracting both forces we get the resultant force on the desk to be: 1157.58 - 370 = 787.58 N

Now lets use F = ma to calculate for the acceleration of the desk:

787.58 = 63 x acceleration

acceleration = 12.501 m/s

Finally, we can use the motion equation:

$v^2 - u^2 = 2*a*s$

here u = 0 m/s (since initial speed of the desk is 0)

a = 12.501 m/s

and s = 10 m

Solving this we get:

$v^2 - 0 = 2 * 12.501 * 10$

$v = 15.812 m/s$

Since the desk and Mr. Dwayne Johnson are connected by a taught rope, they are travelling at the same speed. Thus, Dwayne also travels at 15.812 m/s when the desk reaches the window.

5 0

3 years ago

Why do ionic compounds make good conductors when dissolved in water?

sveticcg [70]

Answer: The correct answer is B- The ions are free to move in water and carry an electric charge.

5 0

3 years ago

An incandescent bulb is supplied with

Serga [27]

Answer:

Efficiency = 5%

Explanation:

Given that,

Supplies energy to the bulb = 100 J

Transferred energy by the bulb = 5 J

We need to find the efficiency of the bulb. It can be given by "

$\eta=\dfrac{\text{useful energy out}}{\text{useful energy in}}\times 100\\\\=\dfrac{5}{100}\times 100\\\\=5\%$

So, the efficiency of the bulb is 5%.

8 0

3 years ago