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.A particle moving with a constant acceleration has a velocity of 20 cm/s when its position is x = 10 cm. Its position 7.0 s later is x = –30 cm. What is the acceleration of the particle?

Respuesta :

Answer:

[tex]4.08cm/s^2[/tex]

Explanation:

The second equation of a uniformly accelerated motion could be used to solve this problem. This is given by equation (1);

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

where u is the particle's initial velocity, t is the time taken, a is the acceleration and s is the distance travelled.

Given;

u = 20cm/s

t = 7s

a = ?

s = ?

The particle moved from one point [tex]x_1[/tex] to another point [tex]x_2[/tex] along the x-axis, where [tex]x_1=10cm[/tex] and [tex]x_2=-30cm[/tex]. This information could be used to find the distance s covered by the object as follows;

[tex]s=x_1-x_2.................(2)\\s=10-(-30)\\s=10+30\\s=40cm[/tex]

We the make appropriate substitutions into equation (1) and then solve for the acceleration.

[tex]40=(20*7)+\frac{1}{2}*a*7^2\\40=140+\frac{1}{2}*a*49\\40=140+24.5a\\40-140=24.5a\\hence\\24.5a=-100\\a=\frac{-100}{24.5}\\a=-4.08cm/s^2[/tex]

The negative sign is an indication that the particle is decelerating.

Answer:

7.347 cm / s²

Explanation:

Using equation of linear motion

S = ut + 1/2 at²

where total displacement = final displacement - initial displacement

S = - 30 - 10 = - 40 cm

- 40 cm = (20 cm /s × 7 s) + 1/2 a (7²)

- 40 cm = 140 cm + 1/2 49 a

- 40 cm - 140 cm =  1/2 × 49 a

- 180 cm × 2 / 49 s² = a

a = -7.347 cm / s²

It is probably decelerating.