Discover the answers you need at Westonci.ca, a dynamic Q&A platform where knowledge is shared freely by a community of experts. Experience the convenience of finding accurate answers to your questions from knowledgeable professionals on our platform. Explore comprehensive solutions to your questions from knowledgeable professionals across various fields on our platform.

A car comes to a stop six seconds after the driver applies the brakes. While the brakes are on, the following velocities are recorded:
Time since brakes applied (sec) 0 2 4 6
Velocity (ft/s) 87 44 16 0
Give lower and upper estimates (using all of the available data) for the distance the car traveled after the brakes were applied.


Sagot :

Answer:

Explanation:

deceleration during first 2 s = (87 - 44) / 2 =21.5 m /s²

deceleration during next 2 s = (44 - 16) / 2 =14 m /s²

deceleration during last  2 s = (16 - 0) / 2 = 8  m /s²

If we assume the acceleration to be uniform during 3 readings

distance travelled during first 2 s

v² - u² = 2 a s

87² - 44² = 2 x 21.5 x s

s = 7569 - 1936 / 43

= 176 m

distance travelled during next 2 s

44² - 16² = 2 x 14 x s

s =  1936 - 256  / 28

= 60 m

distance travelled during last 2 s

16² - 0² = 2 x 8 x s

s =   256  / 16

= 16 m

Total distance travelled = 176 + 60 + 16 = 252 m

If we assume the acceleration as non- uniform , we first calculate average acceleration as follows .

average acceleration = (87 - 0)/ 6 = 14.5 m /s²

v² - u² = 2 a s

87² - 0² = 2 x 14.5 x s

s = 7569  / 29

= 261  m

Hence lower estimate of distance travelled = 252 m ; upper estimate of distance travelled = 261 m .