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Acceleration of a Sport Car

A sport car moving at 60 Km/H accelerates in the distance of 200 m to the speed of 90 Km/H.

Calculate the acceleration of the car.

 

a)

1.51 m/s2

 

b)

0.45 m/s2

 

c)

1.22 m/s2

N

d)

0.87 m/s2

 

e)

None of the above.

 

How long does the car take to reach the final velocity?

N

a)

 9.5 s

 

b)

 7.2 s

 

c)

 3.6 s

 

d)

 1.6 s

 

e)

None of the above.

 

Solution:

Since the question of this problem is the car acceleration, the first step in solving this problem to  change the units of the two velocities to m/s.

and

This problem can be solved using a single formula, , (U_A_M 5). However, the formula need to be solved for the acceleration.

Substituting the known quantities,

The numerical solution has been finally obtained using MathCAD:

Solution:

After calculating the acceleration of the car, the time needs by the car to reach the final velocity can be calculated with the formula , (U_A_M 3). Again, the time needs to be solved from the above formula,

 

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by Luis F. Sez, Ph. D.    Comments and Suggestions: LSaez@dallaswinwin.com