Jill is pushing a box across the floor. Which represents the upward force perpendicular to the floor?

Why do you rotate when you hold a spinning wheel?

choli [55]

When you hold a spinning wheel, the wheel and you, chair included, form a system that obeys the principle of "conservation of angular momentum". This means that any changes in angular momentum within the system must accompanied by an equal and opposite change, so the net force is zero.

4 0

3 years ago

If 28.0 J of work is done by an external force to move a charge from a potential of 8.0 V 8.0 V to a potential of 4.0 V , 4.0 V,

jonny [76]

Answer:

Change in electric potential energy is -28.0 J

Explanation:

Electric potential energy is defined as the work is done to move a charge particle from one position to another in space in the presence of other charge particle or electric potential.

OR

Electric potential energy is also equal to the change in the configuration of the charge particles.

Thus,

Change in electric potential energy = - Work Done

According to the problem, Work Done is equal to 28 J. Thus,

Change in electric potential energy = -28 J

5 0

3 years ago

You have 4.9 g of an unknown substance. To identify the substance, you decide to measure its specific heat and find that it requ

kifflom [539]

The unknown substance can be lithium, which has a specific heat capacity of approximately $3.5 J/gK$ .

Explanation:

When heat energy is supplied to a certain substance, the temperature of the substance increases according to the equation:

$Q=mC_s \Delta T$

where

Q is the amount of energy supplied

m is the mass of the sample

$C_s$ is the specific heat capacity of the substance

$\Delta T$ is the change in temperature

In this problem, we have

m = 4.9 g is the mass

Q = 668.85 J is the specific heat capacity

$\Delta T = 39 K$ is the change in temperature

Solving for $C_s$ , we find the specific heat capacity of the substance:

$C_s = \frac{Q}{m\Delta T}=\frac{668.85}{(4.9)(39)}=3.5 J/gK$

Looking at tables of specific heat capacity, we can see that the unknown substance can be lithium, which has a specific heat capacity of approximately $3.5 J/gK$ .

Learn more about specific heat capacity:

brainly.com/question/3032746

brainly.com/question/4759369

#LearnwithBrainly

3 0

3 years ago

It was once recorded that a Jaguar

Artyom0805 [142]

Answer:

71.85 m/s

Explanation:

Given the following :

Length of skid marks left by jaguar (s) = 290 m

Skidding Acceleration (a) = - 8.90m/s²

Final velocity of jaguar (v) = 0

Speed of Jaguar before it Began to skid =?

Hence, initial speed of jaguar could be obtained using the formula :

v² = u² + 2as

Where

v = final speed of jaguar ; u = initial speed of jaguar(before it Began to skid) ; a = acceleration of jaguar ; s = distance /length of skid marks left by jaguar

0² = u² + (2 × (-8.90) × 290)

0 = u² + (-5,162)

u² = 5162

Take the square root of both sides

u = √5162

u = 71.847 m/s

u = 71.85m/s

6 0

3 years ago

What is know as law of inertia?

schepotkina [342]

Answer:

mark me brianliest plz

Explanation:

Law of inertia, also called Newton's first law, postulate in physics that, if a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force.
Law of Inertia states that a body in a state of rest or uniform motion remains in the same state until and unless an external force acts on it.
A body continues to be in its state of rest or in uniform motion along a straight line unless an external force is applied on it. This law is also called law of inertia.

5 0

2 years ago