Answer:
A) yes
Explanation:
First section of trip: 30 miles in 40 minutes
Second section of trip: 15 miles in 20 minutes
The formula for speed is distance over time
Calculate the speeds for each section of the trip.
First:
k = d/t
k = 30miles/40minutes <= reduce fraction by 10 (30÷10 and 40÷10)
k = 3 miles / 4 minutes
Second:
k = d/t
k = 15miles/20minutes <= reduce fraction by 5 (15÷5 and 20÷5)
k = 3 miles / 4 minutes
Therefore there is a constant speed because both sections of the trip are driving at "3 miles / 4 minutes".
3 miles / 4 minutes can be also formatted as:
0.75 miles per minute.
Answer:
α = 2,857 10⁻⁵ ºC⁻¹
Explanation:
The thermal expansion of materials is described by the expression
ΔL = α Lo ΔT
α =
in the case of the bar the expansion is
ΔL = L_f - L₀
ΔL= 1.002 -1
ΔL = 0.002 m
the temperature variation is
ΔT = 100 - 30
ΔT = 70º C
we calculate
α = 0.002 / 1 70
α = 2,857 10⁻⁵ ºC⁻¹