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3 years ago

A ball starts at rest and rolls down an inclined plane. The ball reaches 7.5 m/s in 3 seconds. What is the acceleration?

Physics

1 answer:

just olya [345]3 years ago

7 0

Answer:

$a=2.5\ m/s^2$

Explanation:

<u>Motion With Constant Acceleration </u>

It's a type of motion in which the velocity of an object changes uniformly over time.

The equation that describes the change of velocities is:

$v_f=v_o+at$

Where:

a = acceleration

vo = initial speed

vf = final speed

t = time

Solving the equation for a:

$\displaystyle a=\frac{v_f-v_o}{t}$

The ball starts at rest (vo=0) and rolls down an inclined plane that makes it reach a speed of vf=7.5 m/s in t=3 seconds.

The acceleration is:

$\displaystyle a=\frac{7.5-0}{3}$

$\boxed{a=2.5\ m/s^2}$

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If you found some sandstone in an ancient river bed, which of these conditions at the time that the sandstone was formed would b

Ulleksa [173]

I believe that the answer to this would be option C. Since sandstones are not commonly seen among river beds, the condition that would make us easier to understand as to what happened to this is how fast the river was flowing. Due to the pressure of the river, this brought other sediments with it most especially sandstones.

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3 years ago

A 12.0 V car battery is being used to power the headlights of a car. Each of the two headlights has a power rating of 41.8 Watts

Marina CMI [18]

Answer:

n = 4.35 x 10¹⁹

Explanation:

Given that

Voltage V= 12 V

Power rating of headlights = 41.8 W

We know that headlights of the car is connected in parallel connection.

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Power = Current x Voltage

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I=3.48 A

Therefore the total current will be

I'= 3.48 + 3.48 A

I = 6.96 A

We know that

Charge = Current x time

q= I' t

q= 6.96 x 1

q= 6.96 C

The charge on electron ,e= 1.6 x 10⁻¹⁹

q= n e

n=Number of electron

$n=\dfrac{q}{e}$

$n=\dfrac{6.96}{1.6\times 10^{-19}}$

n = 4.35 x 10¹⁹

5 0

4 years ago

1. Sang Hee rubs a balloon on her hair until, when she holds the balloon several inches from

vodomira [7]

The reason why Kim's hair rises and sticks out is due to electrostatic attraction.

<h3>What is charging by friction?</h3>

We know that one of the ways in which a body is able to acquire static charges is by friction. When a body is rubbed against another, there could be loss or gain of charges leaving a net charge on each body.

The process that occurs when some of Kim's hair rises and sticks out toward the balloon, even though the balloon hasn't touched her hair is electrostatic attraction.

Learn more about charging by friction:brainly.com/question/9201910

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2 years ago

If you weighted 130 lbs on Earth how much would you weigh on the moon?

In-s [12.5K]

Answer:

Explanation:

Weight on the moon is 16.5 % of weight on earth

Weight on moon = 0.165 * 130

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3 0

3 years ago

Under the influence of its drive force, a snowmobile is moving at a constant velocity along a horizontal patch of snow. When the

balandron [24]

Answer:

a) Δx = 11.6 m

b) t = 3.9 s

Explanation:

Since the snowmobile is moving at constant speed, and the drive force is 195 N, this means that thereis another force equal and opposite acting on it, according to Newton's 2nd Law, due to there is no acceleration present in the horizontal direction .
This force is just the force of kinetic friction, and is equal to -195 N (assuming the positive direction as the direction of the movement).
Once the drive force is shut off, the only force acting on the snowmobile remains the friction force.
According Newton's 2nd Law, this force is causing a negative acceleration (actually slowing down the snowmobile) that can be found as follows:

$a = \frac{F_{fr} }{m} = \frac{-195N}{128kg} = -1.5 m/s2 (1)$

Assuming the friction force keeps constant, we can use the following kinematic equation in order to find the distance traveled under this acceleration before coming to an stop, as follows:

$v_{f} ^{2} -v_{o} ^{2} = 2* a* \Delta x (2)$

Taking into account that vf=0, replacing by the given (v₀) and a from (1), we can solve for Δx, as follows:

$\Delta x =- \frac{v_{o}^{2}}{2*a} =- \frac{(5.90m/s)^{2}}{2*(-1.5m/s2)} = 11.6 m (3)$

We can find the time needed to come to an stop, applying the definition of acceleration, as follows:

$v_{f} = v_{o} + a*\Delta t (4)$

Since we have already said that the snowmobile comes to an stop, this means that vf = 0.
Replacing a and v₀ as we did in (3), we can solve for Δt as follows:

$\Delta t = \frac{-v_{o} }{a} = \frac{-5.9m/s}{-1.5m/s2} = 3.9 s (5)$

7 0

3 years ago