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3 years ago

What is the acceleration of a car that maintains a constant velocity of 100km/h for 10 seconds?

Physics

2 answers:

dusya [7]3 years ago

6 0

A constant velocity means the acceleration is zero.

Zinaida [17]3 years ago

5 0

Answer:0

Explanation: The acceleration of a car that maintains a constant velocity of 100 km/h for 10s is zero. Acceleration is a change in velocity. Thus, if velocity is constant, that means there is no change and velocity stays the same.

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Action potentials _______.(A) are only found at the axon hillock and along the axon.(B) Two of the answers are correct.(C) are v

MAXImum [283]

Answer:

Explanation:

Action potentials are generated at axon hillock because it contains higher density of Na+ channels.From here it is conducted down the axon with equal intensity. It initially depolarizes then polarizes, the order is strict. However, its not affected by the distance they travel.

4 0

3 years ago

Pleaseeee help!!!!!!!!

kenny6666 [7]

Most likely B. Will erode, if not it will grow weeds

6 0

3 years ago

A 1.20-m cylindrical rod of diameter 0.570 cm is connected to a power supply that maintains a constant potential difference of 1

nasty-shy [4]

(a) $1.72\cdot 10^{-5} \Omega m$

The resistance of the rod is given by:

$R=\rho \frac{L}{A}$ (1)

where

$\rho$ is the material resistivity

L = 1.20 m is the length of the rod

A is the cross-sectional area

The radius of the rod is half the diameter: $r=0.570 cm/2=0.285 cm=2.85\cdot 10^{-3} m$ , so the cross-sectional area is

$A=\pi r^2=\pi (2.85\cdot 10^{-3} m)^2=2.55\cdot 10^{-5} m^2$

The resistance at 20°C can be found by using Ohm's law. In fact, we know:

- The voltage at this temperature is V = 15.0 V

- The current at this temperature is I = 18.6 A

So, the resistance is

$R=\frac{V}{I}=\frac{15.0 V}{18.6 A}=0.81 \Omega$

And now we can re-arrange the eq.(1) to solve for the resistivity:

$\rho=\frac{RA}{L}=\frac{(0.81 \Omega)(2.55\cdot 10^{-5} m^2)}{1.20 m}=1.72\cdot 10^{-5} \Omega m$

(b) $8.57\cdot 10^{-4} /{\circ}C$

First of all, let's find the new resistance of the wire at 92.0°C. In this case, the current is

I = 17.5 A

So the resistance is

$R=\frac{V}{I}=\frac{15.0 V}{17.5 A}=0.86 \Omega$

The equation that gives the change in resistance as a function of the temperature is

$R(T)=R_0 (1+\alpha(T-T_0))$

where

$R(T)=0.86 \Omega$ is the resistance at the new temperature (92.0°C)

$R_0=0.81 \Omega$ is the resistance at the original temperature (20.0°C)

$\alpha$ is the temperature coefficient of resistivity

$T=92^{\circ}C$

$T_0 = 20^{\circ}$

Solving the formula for $\alpha$ , we find

$\alpha=\frac{\frac{R(T)}{R_0}-1}{T-T_0}=\frac{\frac{0.86 \Omega}{0.81 \Omega}-1}{92C-20C}=8.57\cdot 10^{-4} /{\circ}C$

5 0

3 years ago

A 500,000 kg cargo ship is traveling at 75 km/h when its engine is shut off. The magnitude of the frictional force between boat

Ymorist [56]

Answer:1.8 hr

Explanation:

Given

mass of cargo=500,000 kg

initial speed $=75 km/h\approx 20.833 m/s$

Frictional force=85 v

at t=0 engine is shut off so acquired speed is slowly decreasing

$85v=-500,000\frac{\mathrm{d} v}{\mathrm{d} t}$

$85dt=-\frac{dv}{v}$

Integrating both sides

$85\int_{0}^{t}dt=-500,000\int_{20.83}^{6.944}\frac{dv}{v}$

$85t=500,000\ln \frac{1}{3}$

t=6462.425 s

t=1.8 hr

4 0

3 years ago

What force acts on a projectile in the horizontal direction?

natita [175]

Answer: horizontal force

Explanation:

i think

3 0

3 years ago

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