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

Answer:

Acceleration is 69.6 m/s²

Explanation:

From the second newton's equation of motion:

${ \boxed{ \bf{s = ut + \frac{1}{2} a {t}^{2} }}}$

substitute the variables:

${ \tt{850 = (54.5 \times 4.22) + ( \frac{1}{2} \times a \times {4.22}^{2}) }} \\ { \tt{850 = 229.99 + 8.9042a}} \\ { \tt{8.9042a = 620.01}} \\ { \tt{a = 69.6 \: {ms}^{ - 2} }}$

Answer 2

Answer:

69.6

Explanation: