If an object with uniform acceleration (or deceleration) has a speed of $12 \frac{m}{s}$ $12 m/s$ at $t = 0$ $t=0$ and moves a total of 145 m by $t = 15$ $t=15$ , what was the object's rate of acceleration?

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Answer 1 · 2018-06-20T15:37:10

The deceleration is $= 0.31 m s^{- 2}$ $=0.31ms^-2$

Apply the equation of motion

$s = u t + \frac{1}{2} a t^{2}$ $s=ut+1/2at^2$

The initial velocity is $u = 12 m s^{- 1}$ $u=12ms^-1$

The distance is $s = 145 m$ $s=145m$

The time is $t = 15 s$ $t=15s$

Therefore,

$145 = 12 \times 15 + \frac{1}{2} a \times 15^{2}$ $145=12xx15+1/2axx15^2$

$\frac{1}{2} a \cdot 225 = 145 - 180 = - 35$ $1/2a*225=145-180=-35$

$a = - 2 \cdot \frac{35}{225} = - 0.31 m s^{- 2}$ $a=-2*35/225=-0.31ms^-2$

If an object with uniform acceleration (or deceleration) has a speed of 12ms12 m/s at t=0t=0 and moves a total of 145 m by t=15t=15, what was the object's rate of acceleration?