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3 years ago

Which of these forces pull or push upward, and which pull or push downward? Explain.

Physics

1 answer:

PtichkaEL [24]3 years ago

8 0

Answer:

A force is a push or pull that acts upon an object as a result of that objects interactions

Explanation:

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Can anyone solve these for my by using unit vectors? Can you also please show your work

Oxana [17]

4. The Coyote has an initial position vector of $\vec r_0=(15.5\,\mathrm m)\,\vec\jmath$ .

4a. The Coyote has an initial velocity vector of $\vec v_0=\left(3.5\,\frac{\mathrm m}{\mathrm s}\right)\,\vec\imath$ . His position at time $t$ is given by the vector

$\vec r=\vec r_0+\vec v_0t+\dfrac12\vec at^2$

where $\vec a$ is the Coyote's acceleration vector at time $t$ . He experiences acceleration only in the downward direction because of gravity, and in particular $\vec a=-g\,\vec\jmath$ where $g=9.80\,\frac{\mathrm m}{\mathrm s^2}$ . Splitting up the position vector into components, we have $\vec r=r_x\,\vec\imath+r_y\,\vec\jmath$ with

$r_x=\left(3.5\,\dfrac{\mathrm m}{\mathrm s}\right)t$

$r_y=15.5\,\mathrm m-\dfrac g2t^2$

The Coyote hits the ground when $r_y=0$ :

$15.5\,\mathrm m-\dfrac g2t^2=0\implies t=1.8\,\mathrm s$

4b. Here we evaluate $r_x$ at the time found in (4a).

$r_x=\left(3.5\,\dfrac{\mathrm m}{\mathrm s}\right)(1.8\,\mathrm s)=6.3\,\mathrm m$

5. The shell has initial position vector $\vec r_0=(1.52\,\mathrm m)\,\vec\jmath$ , and we're told that after some time the bullet (now separated from the shell) has a position of $\vec r=(3500\,\mathrm m)\,\vec\imath$ .

5a. The vertical component of the shell's position vector is

$r_y=1.52\,\mathrm m-\dfrac g2t^2$

We find the shell hits the ground at

$1.52\,\mathrm m-\dfrac g2t^2=0\implies t=0.56\,\mathrm s$

5b. The horizontal component of the bullet's position vector is

$r_x=v_0t$

where $v_0$ is the muzzle velocity of the bullet. It traveled 3500 m in the time it took the shell to fall to the ground, so we can solve for $v_0$ :

$3500\,\mathrm m=v_0(0.56\,\mathrm s)\implies v_0=6300\,\dfrac{\mathrm m}{\mathrm s}$

5 0

4 years ago

A bicycle racer is going downhill at 11.0 m/s when, to his horror, one of his 2.25 kg wheels comes off when he is 75.0 m above t

alex41 [277]

Answer:

a.) Speed V = 29.3 m/s

b.) K.E = 1931.6 J

Explanation: Please find the attached files for the solution

4 0

4 years ago

when a solid wheel rotates about a fixed axis do all of the points of the wheel have the same tangential speed?

vitfil [10]

Yes they should all be going the same speed.

Hope this helped :)

3 0

3 years ago

Read 2 more answers

A hollow spherical shell with mass 1.95 kg rolls without slipping down a slope that makes an angle of 39.0 ∘ with the horizontal

irinina [24]

Answer:0.323

Explanation:

mass of spherical shell=1.95 kg

inclination $\theta =39^{\circ}$

Friction $(f_r)$ will oppose the motion of shell

$mgsin\theta -f_r=ma$

where a=acceleration

a is given by

$a=\frac{gsin\theta }{1+\frac{I}{mr^2}}$

I=moment of inertia $=\fac{2mr^2}{3}$

$a=\frac{3gsin\theta }{5}$

$f_r=mg\sin \theta -\frac{3mgsin\theta }{5}$

$f_r=\frac{2mgsin\theta }{5}$

and $f_r=\mu N$

$f_r=\mu mg\cos \theta$

$\mu mg\cos \theta =\frac{2mgsin\theta }{5}$

$\mu =\frac{2}{5}\times \tan \theta$

$\mu =0.323$

4 0

3 years ago

Hi guys!!! i have no more points, can someone nice guess all of these for me? :)

NeTakaya

1. The ocean water collects back in the ocean.

2. Condensation is the process by which water vapor in the air is changed into liquid water. Condensation is crucial to the water cycle because it is responsible for the formation of clouds.

3. an excessive amount of water flowing from downslope along earths surface

4. A.Evaporation occurs when water is warmed by the sun.

5. The water returns into the ocean by the water cycle . It evaporates , then it condensates , then it participates ( Rains ) and then goes back into the ocean.

Hope this answer correct ✌️

6 0

4 years ago