Question

“a railroad bridge spans a gorge 40 feet wide and connects two cliffs at heights of 98 and 158 feet above the bottom of the gorge. a train is crossing this gorge from the higher cliff to the lower. when the front of the train has traveled three-fourths of the bridge's length, how many feet is it above the bottom of the bottom of the gorge?”

Answer 1

Answer:

Height above the bottom gorge is 113 feet

Step-by-step explanation:

The width of the gorge = 40 feet

The height of the higher cliff = 158 feet

The height of the lower cliff = 98 feet

The length of the bridge = √((158-98)² + 40²) = 72.11 feet

The slope of the bridge = (158-98)/40 = 1.5

The length of 1/4 of the bridge from the lower cliff =72.11 - 3/4×72.11 = 18.03 feet

The angle of inclination of the bridge = tan⁻¹(1.5) = 56.31°

The height above the bottom at 3/4 from the higher cliff = The height above the bottom at 1/4 from the lower cliff = 98+ 18.03×sin(56.31 ) = 113 feet

Which can also be found directly from the heights of the two cliffs knowing that 3/4 from the higher cliff = 1/4 from the lower cliff giving;

Height above the bottom gorge = 98 + 1/4×(158 - 98) = 113 feet.