Answer:
If a car skids 66 ft on wet concrete, it will move at 243 ft/s when the brake is applied.
Explanation:
To determine how fast the car was moving, after skidding, the formula below is used:
V = √32*fd
V is the car's speed (ft/s)
d is skid length (ft) = 66 ft
f is the coefficient of friction determined by the material the car was skidding on.
Coefficient of friction for wet concrete is 0.65
V = √32*fd
V = √32 *0.65* 66
V = 242.679 ft/s ≅ 243 ft/s (nearest whole number)
If a car skids 66 ft on wet concrete, it will move at 243 ft/s when the brake is applied.
Answer:
4.163 m
Explanation:
Since the length of the bridge is
L = 380 m
And the bridge consists of 2 spans, the initial length of each span is
Due to the increase in temperature, the length of each span increases according to:
where
is the initial length of one span
is the temperature coefficient of thermal expansion
is the increase in temperature
Substituting,
By using Pythagorean's theorem, we can find by how much the height of each span rises due to this thermal expansion (in fact, the new length corresponds to the hypothenuse of a right triangle, in which the base is the original length of the spand, and the rise in heigth is the other side); so we find:
Answer:
1) 6 seconds
2) 60 m/s
Explanation:
Given:
Δy = 180 m
v₀ = 0 m/s
a = 10 m/s²
1) Find t.
Δy = v₀ t + ½ at²
180 m = (0 m/s) t + ½ (10 m/s²) t²
t = 6 s
2) Find v.
v² = v₀² + 2aΔy
v² = (0 m/s)² + 2 (10 m/s²) (180 m)
v = 60 m/s
