A 7.80-g bullet moving at 575 m/s strikes the hand of a superhero, causing the hand to move 5.50 cm in the direction of the bullet’s velocity before stopping. (a) Use work and energy considerations to find the average force that stops the bullet. (b) Assuming the force is constant, determine how much time elapses between the moment the bullet strikes the hand and the moment it stops moving.
Answers
Answer:
a)40.77N
b)0.11seg
Explanation:
The bullet has a kinetic energy:
When the bullet stops this energy goes to zero, as the energy must be conserved the work done by the head of the superhero must be equal to the original energy of the bullet:
Considering an average constant force, the work can be calculated as:
Solving for F:
The acceleration(on the opposite direction of motion) on the bullet will be:
The velocity of the bullet considering a constant acceleration can be calculate as:
It stops moving when V=0 so:
Answer:
a) 23444.3 N
b) 0.191 ms
Explanation:
Given:
Mass of the bullet m = 7.8 g = 7.8 * 10⁻³ Kg
Initial speed u = 575 m/s
Final speed v = 0
Distance covered s = 5.50 cm = 0.055 m
(a)
According to work energy theorem
Work done W = Change in Kinetic energy
hence, force*distance = 1/2*mass*velocity²
that is, F*S = (1/2)mu²
F*0.055 = 0.5 * 7.8 * 10⁻³ * (575)^2
F = 23444.3 N
(2)
From Impulse definition
force*time = change in momentum
where momentum = mass * velocity
F*t = Change in momentum = m* u
23444.3t = 7.8*10⁻³ * 575
Time, t = 0.191 ms
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First of all, that's not an equation. An equation needs an 'equals' sign ( = ),
so you need something like
Amount present = a e^-0.0025t .
'a' = amount present when t = 0 .
The half-life is the time it takes for the original amount to decay to half of it.
That's just 't' when e^-0.0025t = 1/2
Take the natural log of each side: -0.0025t = ln(0.5)
Divide each side by -0.0025 : t = ln(0.5) / (-0.0025) =
(-0.69315) / (-0.0025) =
t = 277.26 minutes
( 4hrs 37min 15.5sec)
Rounded to nearest tenth: t = 277.3 minutes .
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One of the type of voice that could produce a pitch that has a speed of 343 m/s and a wavelength of 0.68 m would be soprano
hope this helps
N
2. What is the force of friction acting on the car by the road?.
N
3. What is the coefficient of kinetic friction between the car and the road?
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Answer:
final velocity will be
Explanation:
As we know that initial speed of the car will be
acceleration of the car is
time taken is
now we know that
You take your Initial Velocity and add to it all the gained velocity you get during this process (which is the Acceleration multiplied by the amount of Time you are accelerating for)
So we get (Final Velocity) = (Initial Velocity) + (Time)(Acceleration)
In your equations, thats (Final Velocity) = (10 meters/second) + (5 seconds)(2.1 meters/second/second)
Which is 10 + 10.2 = 20.2 meters/second