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A ball initially at rest rolls down a hill with an acceleration of 3.3 m/s2. If it accelerates for 7.5 s, how far will it move?

Respuesta :

Answer:

  Ball will move 92.8125 meter along the cliff in 7.5 seconds.

Explanation:

We have equation of motion , [tex]s= ut+\frac{1}{2} at^2[/tex], s is the displacement, u is the initial velocity, a is the acceleration and t is the time.

In this case initial velocity = 0 m/s, acceleration = 3.3 [tex]m/s^2[/tex], we need to calculate displacement when time = 7.5 seconds.

Substituting

  [tex]s=0*7.5+\frac{1}{2} *3.3*7.5^2\\ \\ =92.8125 meter[/tex]

  So ball will move 92.8125 meter along the cliff in 7.5 seconds.

The ball will move through a distance of 84.375 m

From the question,

The ball is initially at rest before rolling down the hill

This means the initial velocity, u, of the ball is 0 m/s

To calculate how far the ball move,

From one of the equations of kinematic for linear motion

We have that

[tex]s = ut + \frac{1}{2}at^{2}[/tex]

Where,

s is the distance

u is the initial velocity

a is the acceleration

and t is the time

From the question

u = 0 m/s

a = 3.3 m/s²

t = 7.5 s

Putting these values into the equation

[tex]s = ut + \frac{1}{2}at^{2}[/tex]

We get

[tex]s = 0(7.5) + \frac{1}{2} (3.3)(7.5)^{2}[/tex]

[tex]s = 0+ \frac{1}{2} \times 3.3 \times 7.5^{2}[/tex]

[tex]s = \frac{1}{2} \times 3.3 \times 56.25[/tex]

[tex]s = \frac{168.75}{2}[/tex]

s = 84.375 m

Hence, the ball will move through a distance of 84.375 m

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