Question

Pls answer fast and correctly if incorrect you will be reported

Answer 1

4

Explanation:

I think four is the correct answer

Answer 2

Explanation:

The length of the bridge=4.2km

=4.2 × 1000m

=42000m

The final velocity, V=29m/s

t=4min

=4 × 60s

=240sec

by the equations of motion we have,

V = u+at

Substituting the values we get,

29= u+a× 240 ………(1)

applying to the second equation of motion we get,

S=ut+1 / 2at2

Substituting the values we get,

4200=u × 240 + 12a × (240)2 ………(2)

Multiply equation (1) by we get,

2402×29l

2402×u+a×24022 ……(3)

Subtracting equation (2) by (3) we get,

720 = 120 u

Rearranging the equation we get,

u =720 / 120

u=6m/s

hope it helps you