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3 years ago

6

A sled starts off with an initial velocity of 8 m/s and slows down to 2 m/s after 3 seconds. What was its acceleration?

1 answer:

melomori [17]3 years ago

3 0

Answer:

-2m/s

Explanation:

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How much work is done if you push a 200 N box across a floor with a force of 50 N for a distance of 20m

vovikov84 [41]

<h2>Answer: 1000 J</h2>

The Work $W$ done by a Force $F$ refers to the release of potential energy from a body that is moved by the application of that force to overcome a resistance along a path.

It should be noted that it is a scalar magnitude, and its unit in the International System of Units is the Joule (like energy). Therefore, 1 Joule is the work done by a force of 1 Newton when moving an object, in the direction of the force, along 1 meter:

$1J=(1N)(1m)=Nm$

Now, when the applied force is constant and the direction of the force and the direction of the movement are parallel, the equation to calculate it is:

$W=(F)(d)$ (1)

When they are not parallel, both directions form an angle, let's call it $\alpha$ . In that case the expression to calculate the Work is:

$W=Fdcos{\alpha}$ (2)

For example, in order to push the 200 N box across the floor, you have to apply a force along the distance $d$ to overcome the resistance of the weight of the box (its 200 N).

In this case both <u>(the force and the distance in the path) are parallel</u>, so the work $W$ performed is the product of the force exerted to push the box $F=50N$ by the distance traveled $d$ . as shown in equation (1).

Hence:

$W=(50N)(20m)$

$W=1000Nm=1000J$ >>>>This is the work

8 0

3 years ago

What is the average speed of a car that travels 60 meters in 2<br> seconds?

blondinia [14]

Answer:

30 m/s

Explanation:

Speed is distance over time. 60 meters / 2 seconds, = 30 m/s.

6 0

3 years ago

An object's mass refers to _____ and an object's weight refers to _____. Fill in each blank.

mamaluj [8]

Answer:

c

Explanation:

because the more mass it has the more dense it is

6 0

3 years ago

Which is an si metric unit of measurement that is used to record the heat transfer of a solution in a classroom investigation?

kumpel [21]

The SI unit for heat energy is joule

4 0

3 years ago

Two uniform solid cylinders, each rotating about its central (longitudinal) axis, have the same mass of 3.44 kg and rotate with

Free_Kalibri [48]

Answer:

(a) 20,154.1 J

(b) 95,223.5 J

Explanation:

The expression for the moment of inertia for the uniform solid cylinder is as follows;

$I= \frac{1}{2}mr^{2}$

Here, I is the moment of inertia, r is the radius and m is the mass of the object.

The expression for the rotational kinetic energy is as follows;

$K= \frac{1}{2}I\omega ^{2}$

Here, K is the rotational kinetic energy and $\omega$ is the angular velocity.

(a)

Calculate the moment of inertia of the smaller solid cylinder.

$I= \frac{1}{2}mr^{2}$

Put m= 3.44 kg and r= 0.356 m.

$I= \frac{1}{2}(3.44)(0.356)^{2}$

$I= 0.218 kg m^{2}$

Calculate the rotational kinetic energy of the smaller cylinder.

$K= \frac{1}{2}I\omega ^{2}$

Put $I= 0.218 kg m^{2}$ and $\omega = 430 rads^{-1}$ .

$K= \frac{1}{2}(0.218)(430) ^{2}$

K= 20,154.1 J

Therefore, the rotational kinetic energy for the smaller cylinder is 20,154.1 J.

(b)

Calculate the moment of inertia of the larger solid cylinder.

$I= \frac{1}{2}mr^{2}$

Put m= 3.44 kg and r= 0.775 m.

$I= \frac{1}{2}(3.44)(0.775)^{2}$

$I= 1.03 kg m^{2}$

Calculate the rotational kinetic energy of the smaller cylinder.

$K= \frac{1}{2}I\omega ^{2}$

Put $I= 1.03 kg m^{2}$ and $\omega = 430 rads^{-1}$ .

$K= \frac{1}{2}(1.03)(430) ^{2}$

K= 95,223.5 J

Therefore, the rotational kinetic energy for the larger cylinder is 95,223.5 J.

7 0

4 years ago