10 m/s2 for a distance of 65.2 ft
Answer:
The ladder is moving at the rate of 0.65 ft/s
Explanation:
A 16-foot ladder is leaning against a building. If the bottom of the ladder is sliding along the pavement directly away from the building at 2 feet/second. We need to find the rate at which the top of the ladder moving down when the foot of the ladder is 5 feet from the wall.
The attached figure shows whole description such that,
.........(1)

We need to find,
at x = 5 ft
Differentiating equation (1) wrt t as :



Since, 

At x = 5 ft,


So, the ladder is moving down at the rate of 0.65 ft/s. Hence, this is the required solution.
If an object is on a frictionless surface, to keep it at a constant velocity you can’t apply any force because otherwise, the object will accelerate, and the velocity will change.
I believe the answer would be , it may change from one element to another. I’m saying this because during nuclear transmutation is when a subatomic particle fired at the nucleus of an atom changes into a heavier element , to break the nucleus apart into two nuclei and energy.
Momentum = mass x velocity
Thus Option A is the correct answer
Momentum (dog) = 10 kg x (0.447 x 30) m/s
= 134.1 Kg m/s
Momentum ( bullet) = 0.02 kg x (0.447 x 800) m/s
= 7.152 Kg m/s
Momentum ( truck) = 0, as v = 0
tightrope has both low mass and low speed, thus its momentum will be low