Physics, 04.03.2020 02:26 nahimi

A car of mass m = 1030 kg is traveling down a θ = 13-degree incline. When the car's speed is v0 = 14 m/s, a mechanical failure causes all four of its brakes to lock. The coefficient of kinetic friction between the tires and road is μk = 0.45.
a. Write an expression for the magnitude of the force of kinetic friction
b. Write an expression for the magnitude of the change in the car's height, h, along the y-direction, assuming it travels a distance L down the incline.
c. Calculate the distance the car travels down the hill 1 in meters until it comes to a stop at the end

Answers: 3

Show answers

Answers

Answer from: Jbullon119

a. $F_f = \mu mg cos\theta$

b. h = Lsinθ

c. 22.78 m

Explanation:

a. The kinetic friction is the product of kinetic coefficient and normal force N, which is the gravity force in the direction normal to the incline

$F_f = \mu N = \mu mg cos\theta$

b. As the car travels a distance L down the incline of θ degrees, vertically speaking it would have traveled a distance of:

h = Lsinθ

As we can treat L and h in a right triangle where L is the hypotenuse and h is a side length in opposite of incline angle θ

c. Let g = 9.81 m/s2. the acceleration caused by kinetic friction according to Newton's 2nd law is

$a = F_f/m = \mu g cos\theta = 0.45*9.81*cos13^o = 4.3 m/s^2$

We can use the following equation of motion to find out the distance traveled by the car:

$v^2 - v_0^2 = 2a\Delta s$

where v = 0 m/s is the final velocity of the car when it stops, v_0 = 14m/s is the initial velocity of the car when it starts braking, a = -4.3 m/s2 is the deceleration of the car, and $\Delta s$ is the distance traveled, which we care looking for:

$0^2 - 14^2 = 2(-4.3)\Delta s$

$\Delta s = 14^2 / (2*4.3) = 22.78 m$

Answer from: Quest

this is a good question! i'll do some research and come back when i have the answer!

Strehe name denean expression ordurina liquid of surface to play tobe ofradius 10m stands upright in

Answer from: Quest

russian is not my first language, so i'm afraid i can't write out an answer in russian, but hopefully you can find a way to do so. here's my best translation of the problem: you're given a plot of a particle's position in one-dimensional space over time, and you're asked to find either the total distance traveled by the particle after 6 seconds had elapsed, or the total displacement of the particle after 6 seconds.

if you want the total distance traveled, you would first need to determine the particle's velocity as a function of time, then integrate that over the 6-second interval. we know the position function is quadratic with roots at 0 and 6, so we have

$x(t)=ax(x-6)$

where $a$ is unknown. because the position is parabolic, there is symmetry about the midpoint at $t=3$ , and we know that

$x(3)=10\implies -9a=10\implies a=-\dfrac{10}9$

so that the position function is

$x(t)=-\dfrac{10}9x(x-6)$

which means the velocity is

$v(t)=\dfrac{\mathrm dx}{\mathrm dt}=-\dfrac{20}9x+\dfrac{60}9$

then the total distance traveled is

$\displaystyle\int_{t=0}^{t=6}|v(t)|\,\mathrm dt=\left\{\int_{t-0}^{t=3}-\int_{t=3}^{t=6}\right\}v(t)\,\mathrm dt=20$

so the total distance traveled is 20 m.

on the other hand, if you want to find displacement: the particle starts at $x=0$ and ends at $x=0$ , so its displacement is 0.

Another question on Physics

Physics, 22.06.2019 11:30

In a good thermo flask the main cause of heat loss is

Answers: 1

Answer

Physics, 22.06.2019 15:50

Decreased sensitivity to an unchanging stimulus is known as

Answers: 3

Answer

Physics, 22.06.2019 16:30

An astronaut in space cannot use a scale or balance to weigh objects because there is no gravity. but she does have devices to measure distance and time accurately. she knows her own mass is 77.4 kg , but she is unsure of the mass of a large gas canister in the airless rocket. when this canister is approaching her at 3.50 m/s , she pushes against it, which slows it down to 1.30 m/s (but does not reverse it) and gives her a speed of 2.60 m/s . what is the mass of the canister?

Answers: 1

Answer

Physics, 22.06.2019 17:30

Chameleons catch insects with their tongues, which they can rapidly extend to great lengths. in a typical strike, the chameleon's tongue accelerates at a remarkable 220 m/s2 for 20 ms, then travels at constant speed for another 30 ms.

Answers: 1

Answer

You know the right answer?

A car of mass m = 1030 kg is traveling down a θ = 13-degree incline. When the car's speed is v0 = 14...

Questions