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A car travels 100 m while decelerating to 8 m/s in 5 s.

a) What was its initial speed?
b) What was it's acceleration?

User Mmeany
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1 Answer

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Final answer:

To find the initial speed (u) and acceleration (a) of the car, specific equations of motion are applied using given parameters. The final speed (8 m/s), time (5 s), and distance (100 m) allow for solving two equations to find the car's initial speed and acceleration.

Step-by-step explanation:

To calculate the initial speed of the car, we can use the equation of motion v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration, and t is the time. Rearranging the equation, we get u = v - at. The car's final velocity (v) is 8 m/s and the time (t) is 5 s. However, we still need to calculate the acceleration.

The acceleration can be found using another equation of motion: s = ut + (1/2)at^2, where s is the distance traveled. Given that the distance (s) is 100 m, we can plug the known values into the equation and solve for u and a.

By rearranging the equation s = ut + (1/2)at^2 to s = vt - (1/2)at^2 and substituting v = 8 m/s, t = 5 s, and s = 100 m, we can solve for a and then use the first equation to find u. After solving the equations, we find that the initial speed of the car was u and the acceleration was a m/s^2.

User ScottyDont
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