3 hours and 40 minutes is equivalent to 3.667 hours. If a woman must have run another marathon (of 26.2 miles) within that time, then her minimum average speed in mph can be calculated by dividing the distance by time:
26.2 miles / 3.667 hours = 7.145 miles per hour
Answer:
110 m
Explanation:
Draw a free body diagram of the car. The car has three forces acting on it: normal force up, weight down, and friction to the left.
Sum of the forces in the y direction:
∑F = ma
N − mg = 0
N = mg
Sum of the forces in the x direction:
∑F = ma
-F = ma
-Nμ = ma
Substitute:
-mgμ = ma
-gμ = a
Given μ = 0.40:
a = -(9.8 m/s²) (0.40)
a = -3.92 m/s²
Given that v₀ = 30 m/s and v = 0 m/s:
v² = v₀² + 2aΔx
(0 m/s)² = (30 m/s)² + 2 (-3.9s m/s²) Δx
Δx ≈ 110 m
Answer:
c is correct
Explanation:
Steel is a metal that is made from iron and carbon. During the steel making process, iron & carbon are melted together, and is allowed to harden into a solid. The iron and the carbon DO NOT chemically react with each other. After the steel was made, 20 samples were taken from one piece and tested. Each sample contained 98% iron and 2% carbon.
Which of the following terms BEST describes steel? homogeneous mixture