upon hearing of superman's train pushing adventures, ironman decides he can't be outdone. Ironman finds an abandoned train (m=5400kg) and pushes it with a force of 4000 N, until the speeds up to 5m/s.

Answer 1

First we calculate acceleration:

a = F/m = (4000 N)/(5400 kg) = (20/27) m/s²

If the question is how long does it take Iron Man to achieve the speed of 5 m/s,

then we use the kinematics equation: v – v₀ = at.

Since v₀ = 0, we have

v = at, which means that t = v/a

In this case the answer is

t = (5 m/s)/(20/27 m/s²) = 27/4 = 6.75 s

If the question is how far does Iron Man push the train to achieve the speed of 5 m/s,

then we use the kinematics equation: v² – v₀² = 2ax

Since v₀ = 0, we have

v² = 2ax, which means that x = v²/2a

In this case the answer is

x = (5 m/s)²/(2 × 20/27 m/s²) = (25 m²/s²)/(40/27 m/s²)

= (25 × 27)/40 = (5 × 27)/8 = 135/8 = 16.875 m

Note that after we come up with t = 6.75 s, we can also calculate distance (x) using

x = ½(v₀ + v)t where v₀ = 0 and v = 5:

So x = ½(5)(6.75) = 16.875