Magnetism Assessment
1 answer:
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a) Average velocity for her run north: 2.68 m/s north
b) The average velocity for the whole trip is zero
c) The average speed for the whole trip is 1.95 m/s
Explanation:
a)
In this part of the problem we only want to consider the part when Micha is running north.
The average velocity is given by:
where
d is the displacement (a vector connecting the initial position to the final position of motion)
t is the time
For the part running north, we have
north is the displacement
is the time interval
Substituting,
north (we have to specify also the direction, since velocity is a vector)
b)
As we said, average velocity is given by
where
d is the displacement
t is the time
If we consider the whole trip, however, the displacement is zero:
d = 0
Because Micha returns home, so the initial position corresponds to the final position of motion. Therefore, the average velocity is also zero:
v = 0
c)
The average speed is given by
where
d is the distance covered (the total length of the path, regardless of the direction)
t is the time interval
Since MIcha ran 2 miles north and then 2 miles back, the total distance is
And the time taken is
So, the average speed is
And since speed is a scalar, there is no need to specify a direction.
Learn more about speed and velocity:
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Answer:
a)
b) the motorcycle travels 155 m
Explanation:
Let , then consider the equation of motion for the motorcycle (accelerated) and for the car (non accelerated):
where:
is the speed of the motorcycle at time 2
is the velocity of the car (constant)
is the velocity of the car and the motorcycle at time 1
d is the distance between the car and the motorcycle at time 1
x is the distance traveled by the car between time 1 and time 2
Solving the system of equations:
For the second part, we need to calculate x+d, so you can use the equation of the car to calculate x:
Answer:
dR/dt = 10.2 ft / s
Explanation:
Let's work this problem by finding the distance between the balloon and the motorcycle and then drift for the speed change of the distance
Balloon
y = y₀ + t
Motorcycle
x = v₀ₓ t
Distance, let's use Pythagoras' theorem
R² = x² + y²
R² = (v₀ₓ t)² + (y₀ + t)²
v₀ₓ = 88 ft / s
= 8 ft / s
y₀ = 150 ft
R² = (8 t)² + (150 + 8 t )²
R² = 64 t² + (150 + 8t )²
This is the expression for the distance between the two bodies, the rate of change is the derivative with respect to time (d / dt)
2RdR / dt = 64 2 t + 2 (150 + 8t) 8
dR / dt = [64 t + (1200 + 64t )] / R
dR/dt = (1200 +128 t)/R
Let's calculate for the time of 10 s
dR / dt = (1200 + 128 10) / R = 2480 /R
R = √ [64 10² + (150 + 8 10)²
R = √ [6400 + 52900]
R = 243.5 ft
dR / dt = (2480) / 243.5
dR / dt = 10.2 ft / s