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3 years ago

A roller coaster starts from rest at the top ofan 18m hill.

Physics

1 answer:

KonstantinChe [14]3 years ago

7 0

Answer:

12.65 m/s

Explanation:

When friction is ignored, if the car travels from 18m hill to the bottom of the hill, afterwards it travels up to a 10m hill, then overall it has traveled a distance of 18 - 10 = 8 m vertically.

If the car starts from rest, then its potential energy is converted to kinetic energy:

$E_p = E_k$

$mgh = mv^2/2$

where m is the car mass and h is the vertical distance traveled, v is the car velocity at 10m hill

Let g = 10m/s^2. We can cancel m from both sides of the equation:

$gh = v^2/2$

$v^2 = 2gh = 2*10*8 = 160$

$v^2 = 160$

$v = \sqrt{160} = 12.65 m/s$

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In order to place a satellite into orbit, it requires enough fuel to supply the necessary mechanical energy. Into what types of

nexus9112 [7]

When a satellite is revolving into the orbit around a planet then we can say

net centripetal force on the satellite is due to gravitational attraction force of the planet, so we will have

$F_g = F_c$

$\frac{GM_pM_s}{r^2} = \frac{M_s v^2}{r}$

now we can say that kinetic energy of satellite is given as

$KE = \frac{1}{2}M_s v^2$

$KE = \frac{GM_sM_p}{2r}$

also we know that since satellite is in gravitational field of the planet so here it must have some gravitational potential energy in it

so we will have

$U = -\frac{GM_sM_p}{r}$

so we can say that energy from the fuel is converted into kinetic energy and gravitational potential energy of the satellite

6 0

3 years ago

A gas hot water heater is 65% efficient. The energy output to heat the water is 2.3 kWh.

Art [367]

Answer:

3.5 kWh

1.2 kWh are lost

Explanation:

65=2.3/Ein*100

0.65=2.3/Ein

Ein=2.3/.65

Ein=3.5

3.5-2.3=1.2 kWh

7 0

3 years ago

Perfect square of 11650

suter [353]

Answer:

Since the area of the perfect square is 11650, and all of a squares sides ar equal, we just need to find the square root.

The square root of 11650 is 107.935166.

One side of the square is 107.935166

107.935166 x 107.935166 = 11650

(っ◔◡◔)っ ♥ Hope It Helps ♥

7 0

3 years ago

Read 2 more answers

A 17926-lb truck enters an emergency exit ramp at a speed of 75.6 ft/s. It travels for 6.4 s before its speed is reduced to 30.3

I am Lyosha [343]

Answer:

$F_{braking}=337299 pdl$

Explanation:

Impulse-Momentum relation:

$I=\Delta p\\ F_{total}*t=m(v_{f}-v{o})$

$F_{total}=-F_{braking}+mgsin{\theta}$

We solve the equations in order to find the braking force:

$F_{braking}=m(v_{o}-v{f})/t+mgsin{\theta}=17926(75.6-30.3)/6.4+17926*32.17*sin21.4=337299 pdl$

6 0

3 years ago

Faraday's Law states that the negative of the time rate of change of the flux of the magnetic field through a surface is equal t

MrRa [10]

Answer:

(C). The line integral of the magnetic field around a closed loop

Explanation:

Faraday's law states that induced emf is directly proportional to the time rate of change of magnetic flux.

This can be written mathematically as;

$EMF = -\frac{\delta \phi _B}{\delta t}$

$(\frac{\delta \phi _B}{\delta t} )$ is the rate of change of the magnetic flux through a surface bounded by the loop.

ΔФ = BA

where;

ΔФ is change in flux

B is the magnetic field

A is the area of the loop

Thus, according to Faraday's law of electric generators

∫BdL = $\frac{\delta \phi _B}{\delta t}$ = EMF

Therefore, the line integral of the magnetic field around a closed loop is equal to the negative of the rate of change of the magnetic flux through the area enclosed by the loop.

The correct option is "C"

(C). The line integral of the magnetic field around a closed loop

8 0

4 years ago