Why is it impossible to "defy gravity“?

You are at the carnival with you your little brother and you decide to ride the bumper cars for fun. You each get in a different

Aliun [14]

Answer:

a) The equation is $(m_{b}+m_{c} )u_{b} = (m_{y}+m_{c} )v_{y} + (m_{b}+m_{c} )v_{b}$

b) Your velocity after collision is 2.64 m/s

c) The force you felt is 7392 N

d) you and your brother undergo an equal amount of acceleration

Explanation:

Your mass $m_{y}$ = 60 kg

your brother's mass $m_{b}$ = 30 kg

mass of the car $m_{c}$ = 80 kg

your initial speed $u_{y}$ = 0 m/s (since you've not started moving yet)

your brother's initial velocity $u_{b}$ = 3 m/s

your final speed $v_{y}$ after collision = ?

your brother's final speed $v_{b}$ after collision = ?

a) equations you need to use to figure out how fast you and your brother are moving after the collision is

$(m_{y}+m_{c} )u_{y} + (m_{b}+m_{c} )u_{b} = (m_{y}+m_{c} )v_{y} + (m_{b}+m_{c} )v_{b}$

but $u_{y}$ = 0 m/s

the equation reduces to

$(m_{b}+m_{c} )u_{b} = (m_{y}+m_{c} )v_{y} + (m_{b}+m_{c} )v_{b}$

b) if your little brother reverses with velocity of 0.36 m/s it means

$v_{b}$ = -0.36 m/s (the reverse means it travels in the opposite direction)

then, imputing values into the equation, we'll have

$(m_{b}+m_{c} )u_{b} = (m_{y}+m_{c} )v_{y} + (m_{b}+m_{c} )v_{b}$

(30 + 80)3 = (60 + 80) $v_{y}$ + (30 + 80)(-0.36)

330 = 140 $v_{y}$ - 39.6

369.6 = 140 $v_{y}$

$v_{y}$ = 369.6/140 = 2.64 m/s

This means you will also reverse with a velocity of 2.64 m/s

c) your initial momentum = 0 since you started from rest

your final momentum = (total mass) x (final velocity)

==> (60 + 80) x 2.64 = 369.6 kg-m/s

If the collision lasted for 0.05 s,

then force exerted on you = (change in momentum) ÷ (time collision lasted)

force on you = ( 369.6 - 0) ÷ 0.05 = 7392 N

d) you changed velocity from 0 m/s to 2.64 m/s in 0.05 s

your acceleration is (2.64 - 0)/0.05 = 52.8 m/s^2

your brother changed velocity from 3 m/s to 0.36 m/s in 0.05 s

his deceleration is (3 - 0.36)/0.05 = 52.8 m/s

you and your brother undergo an equal amount of acceleration. This is because you gained the momentum your brother lost

7 0

3 years ago

Calculate the frequency of the 3rd normal mode of a guitar string of length 40.0cm and mass 0.5g when stretched with a tension o

Alexandra [31]

Answer:

Explanation:

For third normal mode of vibration

l = $\frac{3\lambda}{2}$ , λ is wavelength , l is length of string .

.4 = $\frac{3\lambda}{2}$

λ = .267 m

velocity = $\sqrt{\frac{T}{m} }$

T is tension and m is mass unit length

m = .5 x 10⁻³ / 40 x 10⁻²

= .00125 kg / m

Putting the values

velocity = $\sqrt{\frac{80}{.00125} }$

= 253 m /s

frequency

= velocity / λ

= 253 / .267

= 947.5 Hz .

7 0

3 years ago

What is the distance write the equation

Sedbober [7]

Answer:

135 m

Explanation:

Given:

vi = 12 m/s

vf = 18 m/s

t = 9s

Find: x

x = ½ (vf + vi) t

x = ½ (18 m/s + 12 m/s) (9 s)

x = 135 m

5 0

3 years ago

Ik you didnt do the lab but like idek...

serious [3.7K]

Answer:

Speed and direction affect pitch.

4 0

3 years ago

Which statement best describes what Kendall can do?

Vesna [10]

Answer: Explanation:

She can measure the volume and mass of the marble, the volume and mass of the water, and the volume and mass of the graduated cylinder. She can measure the volume and mass of the marble, the volume and mass of the water, and the mass of the graduated cylinder.

5 0

3 years ago