Answer:
185.25 m/s
Explanation:
consider the motion of the combination of bullet and block after the collision
v₀ = initial speed just after the collision
v' = final speed = 0 m/s
μ = Coefficient of friction = 0.6
g = acceleration due to gravity = 9.8 m/s²
a = acceleration of the combination = - μ g = - (0.6) (9.8) = - 5.88 m/s²
d = stopping distance = 13 m
using the kinematics equation
v'² = v₀² + 2 a d
0² = v₀² + 2 (- 5.88) (13)
v₀ = 12.4 m/s
m = mass of the bullet = 9.9 g = 0.0099 kg
M = mass of the wood = 138 g = 0.138 kg
v = speed of bullet before collision
v₀ = speed of combination after the collision = 12.4 m/s
Using conservation of momentum
m v = (m + M) v₀
(0.0099) v = (0.0099 + 0.138) (12.4)
v = 185.25 m/s
Answer:
0.092 m
Explanation:
A charged moving particle immersed in a region with magnetic field follows a circular trajectory at constant speed (uniform circular motion), since the magnetic forces acts perpendicular to the direction of motion of the particle.
Since the magnetic force acts as centripetal force, we can write:
where
q is the charge of the particle
v is its velocity
B is the strength of the magnetic field
m is the mass of the particle
r is the radius of the orbit
Solving the equation for r,
For the ion of oxygen-16, we have:
(it is singly charged)
So the radius of its orbit is
For the ion of oxygen-18, we have:
(it is singly charged)
So the radius of its orbit is
After each ion has travelled a semicircle, the separation between the two ions will be twice the difference in their radius, so:
Explanation:
The buoyant force must be greater to float, otherwise it would sink, its like a barrel in water, the more water weight in it the more it sinks, the more air weight the more it rises.
Actually, they're not. There's a group of stars and constellations arranged
around the pole of the sky that's visible at any time of any dark, clear night,
all year around. And any star or constellation in the rest of the sky is visible
for roughly 11 out of every 12 months ... at SOME time of the night.
Constellations appear to change drastically from one season to the next,
and even from one month to the next, only if you do your stargazing around
the same time every night.
Why does the night sky change at various times of the year ? Here's how to
think about it:
The Earth spins once a day. You spin along with the Earth, and your clock is
built to follow the sun . "Noon" is the time when the sun is directly over your
head, and "Midnight" is the time when the sun is directly beneath your feet.
Let's say that you go out and look at the stars tonight at midnight, when you're
facing directly away from the sun.
In 6 months from now, when you and the Earth are halfway around on the other
side of the sun, where are those same stars ? Now they're straight in the
direction of the sun. So they're directly overhead at Noon, not at Midnight.
THAT's why stars and constellations appear to be in a different part of the sky,
at the same time of night on different dates.
