Answer:
Upward direction.
The friction is kinetic friction
Answer:
4000 km
Explanation:
as we know velocity of electromagnetic wave is c
frequency given (f) = 76 Hz
wavelength ?
using
λ
λ = 
λ = 
≈4000 km
so final answer λ = 4000km
Find the average speed and the average velocity.
Average speed = distance / time
distance = 10 x 8000 m = 80,000 m
time = 20 min * 60 s/min = 1200 s
Average speed = 80,000 m / 1200 s = 66.67 m/s
Average velocity = displacement / time
Given that the race car made complete circles the final poin is the same initial point, then its displacement is zero and the average velocity is zero too.
