Answer:
I think it's
Pumice, cedar, and cork
If I am wrong you have my full permission to correct me :)
- LxlyPxppy <3
Average velocity is defined as
now we have
when she cross the pool in time t1
when she cross the pool back to starting position
Here negative sign is for its return path direction which is reversed of its initial direction.
now for the round trip
displacement = 0
so v = 0
Answer:
Explanation:
1- incident ray
2- the substance through which the wave travels
Answer:
Explanation:
f =
T = 120 N
L = 3.00 m
(m/L) = 120 g/cm(100 cm/m / 1000 g/kg) = 12 kg/m
(wow that's massive for a "rope")
f = )
f = /6 = 0.527 Hz
This is a completely silly exercise unless this "rope" is in space somewhere as the weight of the rope (353 N on earth) far exceeds the tension applied.
A much more reasonable linear density would be 120 g/m resulting in a frequency of √1000/6 = 5.27 Hz on a rope that weighs only 3.5 N
So the person weighs 65kg, and 9.4% of that is head, so 65*0.094 = 6.11 kg is the mass of the head. If we deaccelerate from 40 m/s to 0 m/s in 0.2 s, our total acceleration is: a = Δv/Δt = (0 - 40)/(0.2 - 0) = -200 m/s². We can then use Newton's second law, F = ma, to find the force, using m as mass of the head and a as our acceleration (we'll ignore the negative sign because we don't care about the force's direction here). F = ma = (6.11)(200) = 1222 N, a pretty large amount of force.
It now occurs to me that the easier way to do this, though slightly more advanced, is to use that Force is the derivative of momentum, or F = dp/dt, or with no calculus, F = Δp/Δt, where p is momentum and t is time. p = mv, where m is mass and v is velocity, so F = Δp/Δt = Δ(mv)/Δt = ((6.11)(0) - (6.11)(40))/(0.2 - 0) = (6.11)(40)/(0.2) = 1222 N. So yeah it's quicker, I feel this is less straight forward though.