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3 years ago

When you push a toy car it eventually stops this is due to something called

1 answer:

6 0

Much of what we know about the world today is built upon the work of Sir Isaac Newton, a scientist who lived in the 17th and 18th centuries. He built upon the earlier work of Galileo to develop laws for how motion works in the world. He summarized his work in three laws.

<span>First Law: A moving object tends to keep moving at the same speed and in the same direction unless a force acts on it. An object at rest tends to stay at rest unless a force acts on it.</span>

What does this mean?

It's pretty obvious that a stopped object doesn't move unless someone moves it. The second sentence, however, is harder to believe. It says that objects in motion tend to stay in motion unless stopped by a force. Said another way, until someone or something makes an effort to stop them, they'll keep moving. This tendency of an object to keep moving is called inertia. This is sometimes hard to see in the real world. When you throw a ball, it's going to stop when it hits the ground, even if it rolls for a while. This is because the air that the ball moves through pushes back on it and exerts a force. This pushing back is called friction. The ground also exerts a frictional force as the surface of the ball rubs against the surface of the ground. Without friction a thrown ball would roll forever.

How can I test it?

It's easy to test the first part. Set a ball in a stable position. It doesn't move. If you set it on a hill, it will roll down. That's because gravity exerts a downward force on it.

<span>Now let's build something to test the second part.</span>

You might be interested in

8. An unpowered flywheel is slowed by a constant frictional torque. At time t = 0 it has an angular velocity of 200 rad/s. Ten s

allsm [11]

Answer:

a) $\omega = 50\,\frac{rad}{s}$ , b) $\omega = 0\,\frac{rad}{s}$

Explanation:

The magnitude of torque is a form of moment, that is, a product of force and lever arm (distance), and force is the product of mass and acceleration for rotating systems with constant mass. That is:

$\tau = F \cdot r$

$\tau = m\cdot a \cdot r$

$\tau = m \cdot \alpha \cdot r^{2}$

Where $\alpha$ is the angular acceleration, which is constant as torque is constant. Angular deceleration experimented by the unpowered flywheel is:

$\alpha = \frac{170\,\frac{rad}{s} - 200\,\frac{rad}{s} }{10\,s}$

$\alpha = -3\,\frac{rad}{s^{2}}$

Now, angular velocities of the unpowered flywheel at 50 seconds and 100 seconds are, respectively:

a) t = 50 s.

$\omega = 200\,\frac{rad}{s} - \left(3\,\frac{rad}{s^{2}} \right) \cdot (50\,s)$

$\omega = 50\,\frac{rad}{s}$

b) t = 100 s.

Given that friction is of reactive nature. Frictional torque works on the unpowered flywheel until angular velocity is reduced to zero, whose instant is:

$t = \frac{0\,\frac{rad}{s}-200\,\frac{rad}{s} }{\left(-3\,\frac{rad}{s^{2}} \right)}$

$t = 66.667\,s$

Since $t > 66.667\,s$ , then the angular velocity is equal to zero. Therefore:

$\omega = 0\,\frac{rad}{s}$

7 0

3 years ago

You are walking in Paris alongside the Eiffel Tower and suddenly a croissant falls on your head and knocks you to the ground. If

Alexxandr [17]

Answer:

7,79 seconds

Explanation:

${\overline {a}}={\frac {\Delta v}{t}}$

You need to use the acceleration formula. A is acceliration, $\displaystyle \Delta \mathbf {v}$ is change in velocity and t is time.

You need to multiply the formula with t and divide by a and you get

a*t= $\displaystyle \Delta \mathbf {v}$

t= $\displaystyle \Delta \mathbf {v}$ /a

after that you just need to insert the numbers

change in velocity is 76.4 minus 0.

acceliration is gravitational acceleration which is 9.81.

After that you get

t=76.4/9.81

t= 7,787971458 s

6 0

3 years ago

Read 2 more answers

Vector vector b has x, y, and z components of 4.00, 4.00, and 2.00 units, respectively. calculate the magnitude of vector

Sav [38]

Good morning.

We see that $\mathsf{\overset{\to}{b}} = \mathsf{(4.00, \ 4.00, \ 2.00)}$

The magnitude(norm, to be precise) can be calculated the following way:

$\star \ \boxed{\mathsf{\overset{\to}{a}=(x, y,z)\Rightarrow ||\overset{\to}{a}|| = \sqrt{x^2+y^2+z^2}}}$

Now the calculus is trivial:

$\mathsf{\|\overset{\to}{b} \| =\sqrt{4^2+4^2+2^2} =\sqrt{16+16+4}}\\ \\ \mathsf{\|\overset{\to}{b}\|=\sqrt{36}}\\ \\ \boxed{\mathsf{\|\overset{\to}{b}\| = 6.00 \ u}}$

7 0

3 years ago

Whats the answer to this question show in the picture 2 questions

astraxan [27]

1) D

2) I would say A, but not 100%, its the only one that makes sense tho

3 0

3 years ago

Read 2 more answers

At a depth of 10.9 km, the Challenger Deep in the Marianas Trench of the Pacific Ocean is the deepest site in any ocean. Yet, in

bearhunter [10]

Answer: