Aladder is slipping down a vertical wall. if the ladder is 10 ft long and the top of it is slipping at the constant rate of 4 ft/s, how fast is the bottom of the ladder moving along the ground when the bottom is 8 ft from the wall? round to the nearest tenth.

Speed will be: 1.33ft/s

Explanation:

If ladder is 10 ft long and bottom is 8 ft from the wall then by Pythagoras theorem we can find the height of the wall where ladder touches. (before it started slipping)

thus

Giving x= 6 ft. If the ladder is falling with a speed of 4ft/s it will take 1.5 seconds to cover the 6ft distance.

This shows that the bottom of ladder will travel from 8ft to 10 ft in 1.5 seconds. Thus covering 2 ft in 1.5 seconds making the speed to be:

v = S / t

v = 2 / 1.5

v = 1.33 ft/s

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2