Why does the cyclist have less kinetic energy at position A than at position B?

suppose you walk toward the rear of a moving train describe your motion as seen from a reference point on the train then describ

Alja [10]

From the travel car, it would look like you were running. If you were watching from the top of a tree, you would see the train moving.

5 0

3 years ago

A 50 kg bumper car with a 40 kg child and it is at rest when a 60 kg child in her own bumper car slams into it the collision las

IrinaK [193]

Answer:

F = 99 v₂₀

v₂₀ = 1 m / s, F = 99 N

Explanation:

In this exercise it is asked to find the force during the collision, for this we use the relationship between the momentum and the momentum of car 1

I = Δp

F t = p_f- p₀

F t = m (v_f -v₀) (1)

We must find the final speed of car 1, for this we define a system formed by the two cars, in this case the forces during the collision are internal and the moment is conserved

initial instant. Before the crash

p₀ = 0 + m₂ v₂₀

final instant. After the crash

p_f = m₁ v₁ + m₂ v_{2f}

the moment is preserved

p₀ = p_f

m₂ v₂₀ = m₁ v_{1f} + m₂ v_{2f} (2)

m₂ (v₂₀ - v_2f}) = m₁ v_{1f}

as the collision is elastic the kinetic energy is also conserved

K₀ = K_f

½ m₂ v₂₀² = ½ m₁ v_{1f}² + ½ m₂ v_{2f}²

m₂ (v₂₀² -v_{2f}²) = m₁ v_{1f}²

let's write our system of equations, using

a² - b² = (a + b) (a-b)

m₂ (v₂₀ - v_{2f}) = m₁ v_{1f}

m₂ (v₂₀ -v_{2f}) (v₂₀ + v_{2f}) = m₁ v_{1f}²

to solve we divide the equations

v₂₀ + v_{2f} = v_{1f}

with this we substitute in equation 2 and find the speed of each car, in this case we need the speed of car 1

m₂ v₂₀ = m₁ v_{1f} + m₂ (v_{1f}-v₂₀)

2m₂ v₂₀ = (m₁ + m₂) v_{1f}

v_{1f} = $\frac{2m_2}{m_1+m_2} v_{2o}$

We substitute in the drive ratio of car 1

F t = m (v_f -v₀)

F = m₁ (\frac{2m_2}{m_1+m_2} v_{2o} - 0) / t

F = $\frac{2m_1 m_2 }{m_1+m_2} \ \frac{v_{2o}}{t}$

the mass of each car is the mass of the car plus the mass of the boy

m₁ = 50 +40 = 90 kg

m₂ = 50 +60 = 110 kg

time is t = 1

we substitute the values

F = $\frac{ 2\ 90 \ 110}{90+110} \ \frac{v_{2o}}{1}$ 2 90 100/90 + 110 vo2 / 1

F = 99 v₂₀

The value of the initial velocity of car 2 is not indicated in the problem, if this velocity is known it can be included and the force value is obtained, suppose that the initial velocity v₂₀ = 1 m / s

F = 99 N

4 0

3 years ago

Which idea is associated with Copernicus? Select one: a. The orbits of the planets are circles. b. The orbits of the planets are

Schach [20]

Answer:

d. The earth rotates around the sun

Explanation:

Nicolas Copernicus is considered the first person to give the theory of heliocentric, or Sun-centered system of our planetary system.

In the heliocentric system, it is considered that the sun is stationary and the earth revolves around the sun.

He stated that the sun is at the center of the universe and the earth spins on its axis once daily and revolves around the sun in one year.

And today we know it is correct that earth rotates on its own axis and also revolves around the sun.

8 0

3 years ago

How fast would you be going (in kmh) if you had a ship that accelerated at a constant 1g for 24 hours?

Nady [450]

Answer:

Explanation:

1 g is 9.8 m/s^2 the problem wants the results in km/h so we'll fix that really quick.

9.8 m/s^2 (1 km/1000m)(60 sec/1 min)^2(60 min/1 hour)^2 = 127008 km/hour^2

Now, I'm assuming the ship is starting from rest, and hopefully you know your physics equations. We are going to use vf = vi + at. Everything is just given, or we can assume, so I'll just solve.

vf = vi + at

vf = 0 + 127008 km/hour^2 * 24 hours

vf = 3,048,192 km/hour

If there's anything that doesn't make sense let me know.

5 0

4 years ago

Calculate the self-inductance (in mH) of a 45.0 cm long, 10.0 cm diameter solenoid having 1000 loops. mH (b) How much energy (in

Karo-lina-s [1.5K]

Answer:

(a) The self inductance, L = 21.95 mH

(b) The energy stored, E = 4.84 J

(c) the time, t = 0.154 s