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2 years ago

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Table 2.4 shows how the dispacement of a runner changed during a sprint race. Draw a dispacement-time graph to show this data, a

nd use it to deduce the runner's speed in the middle of the race

1 answer:

GalinKa [24]2 years ago

8 0

4. Table 2.4 shows how the displacement of a runner changed
during a sprint race. Draw a displacement–time graph to show
this data, and use it to deduce the runner’s speed in the middle
of the race.
Table 2.4 Data for a sprinter during a race
Displacement
(m)
0 4 10 20 50 80 105
Time (s) 1 2 3 6 9 12

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A child is running his 46.1 g toy car down a ramp. The ramp is 1.73 m long and forms a 40.5° angle with the flat ground. How lon

frosja888 [35]

Answer:

t=0.704s

Explanation:

A child is running his 46.1 g toy car down a ramp. The ramp is 1.73 m long and forms a 40.5° angle with the flat ground. How long will it take the car to reach the bottom of the ramp if there is no friction?

from newton equation of motion , we look for the y component of the speed and look for the x component of the speed. we can then find the resultant of the speed

$V^{2} =u^{2} +2as$

Vy^2=0+2*9.8*1.73sin40.5

Vy^2=22.021

Vy=4.69m/s

Vx^2=u^2+2*9.81*cos40.5

Vy^2=25.81

Vy=5.08m/s

V=(Vy^2+Vx^2)^0.5

V=47.71^0.5

V=6.9m/s

from newtons equation of motion we know that force applied is directly proportional to the rate of change in momentum on a body.

f=force applied

v=velocity final

u=initial velocity

m=mass of the toy, 0.046

f=ma

f=m(v-u)/t

v=u+at

6.9=0+9.8t

t=6.9/9.81

t=0.704s

4 0

2 years ago

A figure skater rotating at 5.00 rad/s with arms extended has a moment of inertia of 2.25 kgÂ·m2. If the arms are pulled in so t

Serggg [28]

a) 6.25 rad/s

The law of conservation of angular momentum states that the angular momentum must be conserved.

The angular momentum is given by:

$L=I\omega$

where

I is the moment of inertia

$\omega$ is the angular speed

Since the angular momentum must be conserved, we can write

$L_1 = L_2\\I_1 \omega_1 = I_2 \omega_2$

where we have

$I_1 = 2.25 kg m^2$ is the initial moment of inertia

$\omega_1 = 5.00 rad/s$ is the initial angular speed

$I_2 = 2.25 kg m^2$ is the final moment of inertia

$\omega_2$ is the final angular speed

Solving for $\omega_2$ , we find

$\omega_2 = \frac{I_1 \omega_1}{I_2}=\frac{(2.25 kg m^2)(5.00 rad/s)}{1.80 kg m^2}=6.25 rad/s$

b) 28.1 J and 35.2 J

The rotational kinetic energy is given by

$K=\frac{1}{2}I\omega^2$

where

I is the moment of inertia

$\omega$ is the angular speed

Applying the formula, we have:

- Initial kinetic energy:

$K=\frac{1}{2}(2.25 kg m^2)(5.00 rad/s)^2=28.1 J$

- Final kinetic energy:

$K=\frac{1}{2}(1.80 kg m^2)(6.25 rad/s)^2=35.2 J$

7 0

2 years ago

7) A heavy dart and a light dart are launched horizontally on a frictionless table by identical ideal springs. Both springs were

Elenna [48]

Answer:

A, B, and E

Explanation:

The springs are identical, and are compressed the same amount, so they have the same initial elastic potential energy. (E is true)

Energy is conserved, so the darts have the same amount of kinetic energy. (A is true, C is false)

The lighter dart has the same energy as the heavier dart. Since it has less mass, it must have a greater speed. (B is true, D is false)

6 0

2 years ago

Two swift canaries fly toward each other, each moving at 15.0 m/s relative to the ground, each warbling a note of frequency 1750

lesya692 [45]

Answer:

Part a)

f = 1911.5 Hz

Part b)

$\lambda = 0.186 m$

Explanation:

Here the source and observer both are moving towards each other

so we know that the apparent frequency is given as

$f' = f_0 (\frac{v + v_o}{v - v_s})$

here we know that

$f_0 = 1750 Hz$

$v_o = 15 m/s$

$v_s = 15 m/s$

now we will have

$f' = (1750)(\frac{340 + 15}{340 - 15})$

$f' = 1911.5 Hz$

Part b)

Apparent wavelength is given by the formula

$\lambda = \frac{v_{relative}}{f_{app}}$

here we will have

$\lambda = \frac{340 + 15}{1911.5}$

$\lambda = 0.186 m$

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2 years ago

Summarize two of the most common arguments made by animal rights advocates to support the discontinuation of animals in research

Dvinal [7]

Animal rights<span> is the idea that some, or all, </span>non-human animals<span> are entitled to the possession of their own lives and that their most basic interests—such as the need to avoid </span>suffering—should be afforded the same consideration as similar interests of human beings. <span>They maintain that animals should no longer be viewed as property or used as food, clothing, research subjects, entertainment, or beasts of burden.</span>

3 0

2 years ago

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