Following the definition of the center of mass, "In physics, the center of mass of a distribution of mass in space is the unique point where the weighted relative position of the distributed mass sums to zero."
(see explanation below)
Answer:
40 jumping jacks
Explanation:
Period is to the time it takes something to happen. Frequency is a rate quantity. Period is a time quantity. Frequency is the cycles/second.
Since you're walking opposite to the motion of the walkway, the speed
that you walk subtracts from the speed of the belt. Relative to the ground
(the floor of the building), your speed is
(3.4 m/s - 1.5 m/s) = 1.9 m/s
To cover the 84-m length of the walkway, it takes you
(84 m) / (1.9 m/s) = 44.2 seconds .
If you had just stood still and gone with the flow, it would have taken
(84 m) / (3.4 m/s) = 24.7 seconds .
Whereas, if you were willing to put forth the extra effort to keep
walking on the walkway, and had walked forward instead of
backward, then you would have moved at (3.4 + 1.5) = 4.9 m/s
relative to the stationary floor, and you would have covered the
full length of the walkway in only
(84 m) / (4.9 m/s) = 17.1 seconds .
In other words, once you jumped onto the walkway, you had
three options:
-- Stand still, for 24.7 seconds;
-- Walk forward, save 7.6 seconds;
-- Walk backwards, lose 19.5 seconds !
Being in a hurry, your decision to walk backwards was the worst choice.
It was not only totally inexplicable, but it also most likely irritated the other
people on the walkway, as they met you and had to all scrunch to one side
to let you go by in reverse.
It's not surprising that you had to hurry to catch your flight, I'm guessing
that you often miss them.
Answer:
1.93 m/s
Explanation:
Parameters given:
Mass = 4.5g = 0.0045kg
Spring constant = 8.0 N/m
Length of barrel = 13 cm = 0.013m
Frictional force = 0.035N
Compression = 5.8 cm = 0.058m
First, we find the P. E. stored in the spring:
P. E. = ½*k*x²
P. E. = ½ * 8 * 0.058² = 0.013J
Then, we find the work done by the frictional force while the sphere is leaving the barrel of the gun:
Work = Force * distance
The distance here is the length of the barrel.
Work = 0.035 * 0.13 = 0.0046 J
The kinetic energy of the sphere can now be found:
K. E. = P. E. - Work done
K. E. = 0.013 - 0.0046 = 0.0084J
We can now find the speed using the formula for K. E.:
K. E. = ½*m*v²
0.0084 = ½ * 0.0045 * v²
v² = 0.0084/0.00255 = 3.733
=> v = 1.93 m/s
A sound wave is a longitudinal wave