Question

a car moving at 10m/s, accelerated uniformely over a distance of 25m, at the end of which the velocity of the car became 15m/s. determine the acceleration of the car and the time taken to cover the 25m

Answer 1

Solution.

$\upsilon_0=10 m/s;$

$S=25m;$

$\upsilon=15 m/s;$

$a - ?; t - ?$

$S = \dfrac{\upsilon^2 -\upsilon_0^2 }{2a}; \implies a=\dfrac{\upsilon^2 -\upsilon_0^2 }{2S};$

$a=\dfrac{(15 m/s)^2 -(10 m/s)^2 }{2\sdot25 m}=2.5 m/s^2;$

$S = \dfrac{\upsilon +\upsilon_0 }{2}\sdot t \implies t = \dfrac{2\sdot S }{\upsilon +\upsilon_0};$

$t = \dfrac{2\sdot25 m }{ 15 m/s+10 m/s}=2s;$

Answer:$a=2.5 m/s^2; t = 2s.$