Question

What is the acceleration of a skier that slows down from 18 m/s to 9 m/s in 3 seconds?


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Answer 1

Answer:

• 3m/s² is the required acceleration.

Explanation:

According to the Question

It is given that,

• Initial velocity ,u = 18m/s
• Final Velocity ,v = 9m/s
• Time taken ,t = 3

we have to calculate the acceleration of the skier.

As we know that acceleration is defined as the rate of change in velocity at per unit time.

• a = v-u/t

by putting the value we get

↠ a = 9-18/3

↠ a = -9/3

↠ a = -3m/s²

Here, negative sign show retardation (negative acceleration)

• Hence, the acceleration of the skier is 3 m/s².

Answer 2

✴ Given :

• ➲ Intial Velocity of skier

➪ = 18 m/s

• ➲ Final Velocity of skier

➪ = 9 m/s

• ➲ Time Taken

➪ = 3 seconds

▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬

✴ To Find :

• ➲ Acceleration = ?

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✴ Solution :

➟ How to Solve ?

➥Learn first what is acceleration and what is the formula of acceleration.

$\qquad{━━━━}\qquad{━━━━}\qquad{━━━━}$

✴ Acceleration

• ⌧ Velocity per unit time or rate of velocity respect to time,in terms of both speed and direction is called Acceleration .

• ⌧ The S.I unit of acceleration is m / s ²

• ⌧ An object is said to be accelerated if there is a change in its velocity.

• ⌧ Because of Acceleration there is change in the velocity of an object and there could be an increase or decrease in speed or a change in the direction of motion.

• ⌧ There is change in velocity and time of skier so there is a change in direction of a moving object (skier) or an increase or decrease in speed due to this acceleration occurs.

✴ Formula used

• The formula of acceleration is

$\qquad{:\implies{\sf{ Acceleration = \dfrac{ = Final \:Velocity - Initial \: velocity}{Time} }}}$

$\qquad{:\implies{\sf{ Acceleration = \dfrac{ =Change \: in \: Velocity }{Time} }}}$

$\qquad{:\implies{\sf{ Acceleration = \dfrac{ v \: f - v \: i }{t} }}}$

✴ Place the given value in Formula

⌦ Where,

➾ a is the acceleration in m.s-²

➾ v f is the final velocity in m.s-¹

➾ vi is the initial velocity in m.s-¹

➾ t is the time interval in seconds

$\qquad{:\implies{\sf{ Acceleration = \dfrac{ 9- 18}{3} }}}$

$\qquad{:\implies{\sf{ Acceleration = \dfrac{ - 9}{3} }}}$

$\qquad{:\implies{\bf{ Acceleration = -3 \: m/ {s}^{2} }}}$

✴ Therefore

$\qquad{━━━━}\qquad{━━━━}\qquad{━━━━}$

❝ The acceleration of skier is

➩ 3 m / s² ❞

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