Find the time taken if the speed of a train increased rom 72km/h to 90km/h for 234km

2.89 hours

Explanation:

given :

Vo = 72 km/h

Vt = 90 km/h

S = 234 km

find : the time taken (t) = ?

solution :

2.a.s = Vt² - Vo²

2.a.(234) = 90²- 72²

468.a = 8100 - 5184

= 2916

a = 2916/468 = 6.23 km/h²

so,

t = (Vt-Vo) /a

= (90-72)/ 6.23

= 18/ 6.23

= 2.89 hours

Explanation:

s = s₀ + v₀t + ½at²

Let s₀ = 0 be the position in km where acceleration starts,

Let t be in hours

a = (90 - 72) / t = 18/t  km/hr²

234 = 0 + 72t + ½(18/t)t²

234 = 72t + 9t

234 = 81t

t = 2.88888... ≈ 2.89 hr

the expression 15n + 2(3p) represents the amount isaiah spent buying gasoline and snacks, where n represents the price of each gallon of gasoline and p represents the cost of each snack that he bought. which statement is true about the amount isaiah spent?

hi there!

out of the two, (b) precision would be more reasonable.   however, both a and b could be pretty reasonable.

-awesomerepublic   : )