micrometer is used to measure the diameter of a thin wire
Answer:
7.0 s, 69 m/s
Explanation:
If we take down to be positive, then the time to reach the ground is:
x = x₀ + v₀ t + ½ at²
240 m = (0 m) + (0 m/s) t + ½ (9.8 m/s²) t²
t = 7.0 seconds
The final velocity is:
v² = v₀² + 2a(x - x₀)
v² = (0 m/s)² + 2(9.8 m/s²) (240 m - 0 m)
v = 69 m/s
The first thing you should know for this case is that work is defined as the product of force by the distance traveled in the direction of force.
We have then:
W = Fd
The distance varies, so we must integrate:
from 0 to 20:
W = ∫F (x) dx
W = ∫32xdx
W = 32∫xdx
W = 32 (x ^ 2/2) = (16) (20 ^ 2) = 6400 ft * lbs
answer:
6400 ft * lbs is work done pulling the rope up 20 ft
When hot tea is mixed to chilled coke, tea loses heat and coke gains heat. Thus, tea cools down but coke gets heated. Because it is liquid and liquid does not totally cool down to the ambient temperature, it and the iced drink will eventually reach the same temperature.
