The front of a train 80m long passes a signal at a speed of 72km/h. If the rear of the train passes the signal 5seconds later, find (a) the acceleration of the train (b) the speed at which the rear of the train passes the signal.


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Question Number 191091 by otchereabdullai last updated on 18/Apr/23

$T h e f r o n t o f a t r a i n 80 m l o n g p a s s e s$ $a s i g n a l a t a s p e e d o f 72 k m / h . I f t h e$ $r e a r o f t h e t r a i n p a s s e s t h e s i g n a l$ $5 s e c o n d s l a t e r, f i n d$ $(a) t h e a c c e l e r a t i o n o f t h e t r a i n$ $(b) t h e s p e e d a t w h i c h t h e r e a r o f t h e$ $t r a i n p a s s e s t h e s i g n a l .$
	Answered by mr W last updated on 18/Apr/23

	$v_{1} = 72 k m / h = 20 m / s$ $s = v_{1} t + \frac{{a t}^{2}}{2}$ $80 = 20 \times 5 + \frac{a \times 5^{2}}{2}$ $\Rightarrow a = - \frac{8}{5} = - 1.6 m / s^{2}$ $v_{2} = v_{1} + a t = 20 - 1.6 \times 5 = 12 m / s = 43.2 k m / s$
	Commented by otchereabdullai last updated on 18/Apr/23

	$M a y A l l a h a l m i g h t y b l e s s y o u$
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