Ask question

Ask question

All categories

3 years ago

8

Hannah, who has a mass of 65 kg, is riding at 25 m/s in her sports car when she must suddenly swerve off the road to avoid

1 answer:

Annette [7]3 years ago

7 0

Hannah comes to a rest in <em>t</em> = 0.4 s, so her acceleration is

<em>a</em> = (0 - 25 m/s) / (0.4 s) = -62.5 m/s²

(that is, the acceleration points in the direction opposing her movement forward as she brakes)

Then the force exerted on her by the seatbelt has magnitude

<em>F</em> = (65 kg) (62.5 m/s²) = 4062.5 N ≈ 4063 N

You might be interested in

I need help with answer 51.

Troyanec [42]

Answer:

2

Explanation:

5 0

2 years ago

An evacuated long tube contains a coin and a feather. If both objects fall together starting from the top of the tube, it is exp

Natasha_Volkova [10]

Answer:

gexp = 3.65 m/s²

Explanation:

The value of acceleration due to gravity changes with the altitude. The following formula gives the value of acceleration due to gravity at some altitude from the sea level:

gexp = g(1 - 2h/Re)

where,

gexp = expected value of g at altitude = ?

g = acceleration due to gravity at sea level = 9.8 m/s²

h = altitude = 2000 km = 2 x 10⁶ m

Re = Radius of Earth = 6.37 x 10⁶ m

Therefore,

gexp = (9.8 m/s²)(1 - 2*2 x 10⁶ m/6.37 x 10⁶ m)

<u>gexp = 3.65 m/s²</u>

5 0

3 years ago

If the sun is 400 times bigger than the moon, how couild the moon possibly cover the sun during a solar eclipse?

AlekseyPX

Explanation:

the Moon passes between Earth and the Sun Even though the Moon is much smaller than the Sun, because it is just the right distance away from Earth, the Moon can fully block the Sun's light from Earth's perspective This completely blocks out the Sun's light

3 0

3 years ago

Read 2 more answers

A 2.0 m length of wire is made by welding the end of a 120 cm long silver wire to the end of an 80 cm long copper wire. Each pie

Levart [38]

<u>Explanation</u>:

Resistivity of silver wire = $1.47 e-8 ohm meter$

Resistivity of copper wire = $1.72 \mathrm{e}-8 \text { ohm meter }$

Resistance = Resistivity *length/cross sectional area

$R=\rho_{L / A}$

So,

$\begin{aligned}&I=A\left(V / P_{A g} L_{A g}+P_{C u} L C_{U}\right)\\&1=8104 \mathrm{A}\end{aligned}$

For E calculation

For copper

E = resistivity * current density

E = Resistivity * current/area

$E=4.9298 \mathrm{V} / \mathrm{m}$

For silver

$E=4.213 \mathrm{V} / \mathrm{m}$

Potential difference $=E^{*} L$

For silver

Potential difference = $4.213^{*} 1.2=5.055 \mathrm{V}$

For copper

Potential difference = $3.9438 \mathrm{V}$

7 0

3 years ago

Approximate the human form as an unclothed vertical cylinder of 0.3 m diameter and 1.75 m length with a surface temperature of 3

Zolol [24]

Answer:

$q=1118.865W$

Explanation:

From the question we are told that

Diameter of the cylinder $D=0.3m$

Length of the cylinder $L=1.75m$

Surface temperature of cylinder $T_s=30 \textdegree C=303k$

Speed of air $V=10m/s$

Temperature of air $T=20 \textdegree C$

Generally the equation for Reynolds number is mathematically given by

$Re_D=\frac{VD}{v}$

where

$v=15.27*10^-^6$

$Re_D=\frac{10*0.3}{15.27*10^-^6}$

$Re_D=1.96*10^5$

Generally the equation for Nusselt number is mathematically given by

$N_u=0.6(Re_D)^{0.6}(Pr)^{0.37}$

where

Prandtl number

$Pr=0.71$

$N_u=0.6(Re_D)^{0.6}(Pr)^{0.37}$

$N_u=0.6(1.96*10^5)^{0.6}(0.71)^{0.37}$

$N_u=791.53$

Generally the equation for convective heat transfer is mathematically given by

$h=Nu \frac{k}{D}$

where

$k=25.7*10^{-3}$

$h=791.53*\frac{25.7*10^{-3}}{0.3}$

$h=67.81W/m^2K$

Generally the equation for surface area of a cylinder is mathematically given by

$A=\pi DL$

$A=\pi *0.3*1.75$

$A=1.65m^2$

Generally the equation for convective heat transfer is mathematically given by

$q=h4(T_s-T_{inty)}$

$q=(67.81)*1.65*(30-20)\\$

$q=1118.865W$

3 0

3 years ago