Question

Superman is flying 54.5 m/s when he sees

a train about to fall into a river 850 m
away. He must reach the train in 4.22 s.
What acceleration does he need?
(Unit = m/s^2)

Answer 1

69.6

Step-by-step explanation:

Answer 2

Acceleration is 69.6 m/s²

Step-by-step explanation:

From the second newton's equation of motion:

`{ \boxed{ \bf{s = ut + (1)/(2) a {t}^(2) }}}`

substitute the variables:

`{ \tt{850 = (54.5 * 4.22) + ( (1)/(2) * a * {4.22}^(2)) }} \\ { \tt{850 = 229.99 + 8.9042a}} \\ { \tt{8.9042a = 620.01}} \\ { \tt{a = 69.6 \: {ms}^( - 2) }}`