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3 years ago

A motor requires 400 joules of energy to lift a 5.0 kg mass 2.0 meters. Calculate the efficiency of this motor.

Physics

1 answer:

Sauron [17]3 years ago

4 0

Answer:

25%

Explanation:

use F=mg

then use the answer you get from that and plug it into W=Fxh

take that answer and divide it by 400 J and multiply by 100

round to sig figs

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A 975-kg sports car (including driver) crosses the rounded top of a hill at determine (a) the normal force exerted by the road o

iVinArrow [24]

There are missing data in the text of the problem (found them on internet):
- speed of the car at the top of the hill: $v=15 m/s$
- radius of the hill: $r=100 m$

Solution:

(a) The car is moving by circular motion. There are two forces acting on the car: the weight of the car $W=mg$ (downwards) and the normal force N exerted by the road (upwards). The resultant of these two forces is equal to the centripetal force, $m \frac{v^2}{r}$ , so we can write:
$mg-N=m \frac{v^2}{r}$ (1)
By rearranging the equation and substituting the numbers, we find N:
$N=mg-m \frac{v^2}{r}=(975 kg)(9.81 m/s^2)-(975 kg) \frac{(15 m/s)^2}{100 m}=7371 N$

(b) The problem is exactly identical to step (a), but this time we have to use the mass of the driver instead of the mass of the car. Therefore, we find:
$N=mg-m \frac{v^2}{r}=(62 kg)(9.81 m/s^2)-(62 kg) \frac{(15 m/s)^2}{100 m}=469 N$

(c) To find the car speed at which the normal force is zero, we can just require N=0 in eq.(1). and the equation becomes:
$mg=m \frac{v^2}{r}$
from which we find
$v= \sqrt{gr}= \sqrt{(9.81 m/s^2)(100 m)}=31.3 m/s$

7 0

4 years ago

Calculate delta g for the reaction if the partial pressures of the initial mixture are pcl5 = .0029 atm, pcl3 = .27 atm, and pcl

AnnyKZ [126]

Answer: equation for the reaction is given below

PCL2+PCL3=PCL5

Where pcl2=0.40atm,pcl3=0.27atm

Pcl5=0.0029atm

Using ∆G=-RTin(PCL5/PCl2*PCL3)

Where R=8.314J/K/mol and T=298K

∆G=-8.314*298in(0.0029/0.40*.27)

∆G=8962.6J/mol

Explanation:

7 0

4 years ago

Four states of matter and describe the particles arrangement of each

frutty [35]

Answer:

There are four natural states of matter: Solids, liquids, gases and plasma.

Explanation:

The fifth state is the man-made Bose-Einstein condensates. In a solid, particles are packed tightly together so they don't move much.

4 0

3 years ago

Carrie observes a blue object. Which color(s) of light does this object absorb

Ronch [10]

The object carries all colors except blue.

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3 years ago

An electron is projected with an initial speed v0 = 1.10 x 10⁶ m/s into the uniform field between the parallel plates. The dista

ArbitrLikvidat [17]

Answer:

a) $E=364N/C$

b) No

Explanation:

A) Because the electron is affected by an acceleration force in this case by the electric field, we can use the formulas of 2-dimension movement.

We will assume the electron missed the upper plate, so we need to calculate the time to travel all the way through the plate, that is:

$x=v_x*t$

$where:\\x=distance\\v=speed\\t=time$

so:

$t=\frac{x}{v_x}=\frac{0.02m}{1.6\cdot 10^6m/s}\\\\t=1.25\cdot10^{-8}$

the electron experiences an accelerated motion in the vertical direction, so we can obtain the acceleration of the electron:

$y=\frac{1}{2}.a.t^2\\\\where:\\y=vertical\_distance\\a=acceleration\\t=time$

so:

$a=\frac{2.y}{t^2}\\\\a=\frac{2*(\frac{0.01}{2}m)}{(1.25\cdot10^{-8}s)^2}\\\\a=6.4\cdot10^{13} m/s^2$

now we can use the relation:

$F=m.a=E.q\\so\\E=\frac{m.a}{q}$

$where:\\\\E=electric\_field\\m=electron\_mass=9.1\cdot10^{-31}kg\\q=Charge=1.6\cdot10^{-19}\\a=acceleration$

Now we can calculate the electric field:

$E=\frac{9.1\cdot10^{-31}kg\cdot6.4\cdot10^{13}m/s^2}{1.6\cdot10^{-19}C}\\\\E=364N/C$

B) Because the proton has the same charge but positive it will go in the opposite direction, so because we assume the electron didn't touch the plate, the proton won't.

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3 years ago