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3 years ago

A dropped ball accelerates as it falls. but a ball rolling on a horizontal surface has zero acceleration because _______.

Physics

2 answers:

svet-max [94.6K]3 years ago

5 0

Answer:

There is no force acting on it.

Explanation:

The dropping ball experiences the force of gravity on it that make sit accelerate towards the ground constantly, if the ball is rolling on a horizontal surface the effect of the gravity will just have an effect on the weight of the ball and the friction, but unless you are applying an external continuos force to that ball it would not experience acceleration.

nordsb [41]3 years ago

4 0

During a fall, the ball experiences an external force which is acted upon by gravity. This gravitation force induces a constant gravitational acceleration on the object equivalent to 9.81 meters per square second. Hence, the dropped ball is accelerating.

On the other hand, the ball does not experience external force hence the acceleration is zero.

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Two metal disks, one with radius R1 = 2.45 cm and mass M1 = 0.900 kg and the other with radius R2 = 5.00 cm and mass M2 = 1.60 k

larisa86 [58]

Answer:

part (a) $a_1\ =\ 2.9\ kg$

Part (b) $a_2\ =\ 6.25\ kg$

Explanation:

Given,

Mass of the larger disk = $M_2\ =\ 1.60\ kg$
Mass of the smaller disk = $M_1\ =\ 0.900\ kg$
Radius of the larger disk = $R_2\ =\ 5.00\ cm\ =\ 0.05\ m$
Radius of the smaller disk = $R_1\ =\ 2.45\ cm\ =\ 0.0245\ m$
Mass of the block = M = 1.60 kg

Both the disks are welded together, therefore total moment of inertia of the both disks are the summation of the individual moment of inertia of the disks.

$\therefore I\ =\ I_1\ +\ I_2\\\Rightarrow I\ =\ \dfrac{1}{2}M_1R_1^2\ +\ \dfrac{1}{2}M_2R_2^2\\\Rightarrow I\ =\ \dfrac{1}{2} (0.9\times 0.0245^2\ +\ 1.60\times 0.05^2)\\\Rightarrow I\ =\ 2.27\times 10^{-3}\ kgm^2$

part (a)

Given that a block of mass m which is hanging with the smaller disk,

Let 'T' be 'a' be the tension in the string and acceleration of the block.

From the free body diagram of the smaller block,

$mg\ -\ T\ =\ ma\\\Rightarrow T\ =\ mg\ -\ ma\,\,\,\,eqn (1)$

From the pulley,

$\sum \tau\ =\ I\alpha\\\Rightarow T\times R_1\ =\ I\alpha\ =\ \dfrac{Ia}{R_1}\\\Rightarrow T\ =\ \dfrac{I\alpha}{R_1^2}\,\,\,eqn(2)$

From the equation (1) and (2),

$mg\ -\ ma\ =\ \dfrac{Ia}{R_1^2}\\\Rightarrow a\ =\ \dfrac{mg}{\dfrac{I}{R_1^2}\ +\ m}\\\Rightarrow a\ =\ \dfrac{1.60\times 9.81}{\dfrac{2.27\times 10^{-3}{0.0245^2}}\ +\ 1.60}\\\Rightarow a\ =\ 2.91\ m/s^2$

part (b)

Above expression for the acceleration of the block is only depended on the radius of the pulley.

Radius of the larger pulley = $R_2\ =\ 0.05\ m$

Let $a_2$ be the acceleration of the block while connecting to the larger pulley. $\therefore a\ =\ \dfrac{mg}{\dfrac{I}{R_2^2}\ +\ m}\\\Rightarrow a\ =\ \dfrac{1.60\times 9.81}{\dfrac{2.27\times 10^{-3}{0.05^2}\ +\ 1.60}}\\\Rightarow a\ =\ 6.25\ m/s^2$

4 0

3 years ago

What two factors determine the color of an object?

slamgirl [31]

<h3><u>Answer;</u></h3>

4. the material the object is made of and the color of light that strikes it

<h3><u>Explanation;</u></h3>

The color of an object is the wavelength of light that the object reflects, which is determined by the arrangement of electrons in the atoms of the material making the object.
<em><u>We could therefore say that the color of object depends on or is determined by the material making up the object as this determines the the wavelengths of light the object reflects. Lastly, the color of light source also determines the color of the object.</u></em>

3 0

3 years ago

Read 2 more answers

Water pressure increases as

ra1l [238]

My guess is A. depth increases because I know that the deeper you go in the ocean, the higher the water pressure is (which makes it difficult to explore).

7 0

3 years ago

A 1 kg ball moving horizontally to the right at 3 m/s strikes a wall and rebound, moving horizontally to the left at the same ve

Airida [17]

Answer:

The magnitude of the change in linear momentum of the ball is 6 kg-m/s.

Explanation:

Given that,

Mass of the ball, m = 1 kg

Initial sped of the ball, u = 3 m/s

It strikes a wall and rebound, moving horizontally to the left at the same velocity of 3 m/s, v = -3 m/s

The magnitude of the change in linear momentum of the ball is given by :

$p=m(v-u)\\\\p=1\ kg\times (-3-3)\\\\p=-6\ kg-m/s$

So, the magnitude of the change in linear momentum of the ball is 6 kg-m/s.

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4 years ago

as you take a short canoe trip on the Brazos River you paddle your canoe 200 miles up the river in 420 seconds and then turn aro

Maurinko [17]

200 miles/420 secs = 10/21
350 mile/280 secs = 5/4

(5/4+10/21)/2= 145/168 miles per sec
or .86 miles/sec

8 0

3 years ago