Ask question

Ask question

All categories

3 years ago

9

What can be said about the sign of the work done by the force f⃗ 1??

1 answer:

Tju [1.3M]3 years ago

5 0

I did not get your question properly

You might be interested in

Assuming 95.0% efficiency for the conversion of electrical power by the motor, what current must the 12.0-V batteries of a 708-k

Varvara68 [4.7K]

Answer:

a) $I=646.9298\ A$

b) $I=1942.018\ A$

Explanation:

Given:

efficiency of the motor, $\eta=0.95$

voltage of the battery, $V=12\ V$

mass of the car, $m=708\ kg$

a)

initial velocity, $u=0\ m.s^{-1}$

final velocity, $v=25\ m.s^{-1}$

time taken for the acceleration, $t=1\ min=60\ s$

Now we know by the Newton's second law of motion:

$F=m.a$

$F=708\times \frac{(25-0)}{60}$

$F=295\ N$

Now the power will be :

$P=F.v$

$P=295\times 25$

$P=7375\ W$

<u>According to the question:</u>

0.95 times of the electrical power should yield this mechanical power.

$P=V.I\times 0.95$

$7375=12\times I\times 0.95$

$I=\frac{7375}{12\times 0.95}$

$I=646.9298\ A$

b)

height climbed by the car, $h=200\ m$

velocity of climb, $v=25\ m.s^{-1}$

time taken to climb the height, $t=2\ min=120\ s$

force exerted to overcome air and frictional resistances, $f=423\ N$

Now the Power required to climb the hill:

$P=\frac{m.g.h}{t} +f\times v$

$P=\frac{708\times 9.8\times 200}{120}+423\times 25$

$P=22139\ W$

<u>Now according to the electrical efficiency:</u>

$P=V.I\times 0.95$

$22139=12\times I\times 0.95$

$I=1942.018\ A$

7 0

4 years ago

Read 2 more answers

4) The components of Vector A are given as follows Ax = -2.4 Ay = + 3.8 What is the magnitude of the A, and what is the angle th

Monica [59]

Answer:

A = 4.49

α = 57.72°

Explanation:

Knowing the magnitude of x & y of a vector we can determine the total magnitude of a vector.

$A=\sqrt{A_{x}^{2} +A_{y}^{2} } \\A=\sqrt{(2.4)^{2} +(3.8)^{2} }\\A=4.49$

The angle tangent can be used to determine the angle.

$tan(\alpha )=\frac{3.8}{2.4}\\tan(\alpha ) =1.5833\\\alpha =tan^{-1}(1.5833) \\\alpha = 57.72 (deg)$

5 0

3 years ago

U WILL GET 25 POINTS PLEASE HELP

balandron [24]

Answer:

Hopefully, this is right.

Explanation:

Answer is 5.43.

3 0

3 years ago

A net force of 50 N causes a mass to accelerate at a rate of 6.8 m/s2. Determine the mass.

Taya2010 [7]

Force=50N
Acceleration=6.8m/s^2

$\\ \sf\longmapsto F=ma$

$\\ \sf\longmapsto m=\dfrac{F}{a}$

$\\ \sf\longmapsto m=\dfrac{50}{6.8}$

$\\ \sf\longmapsto m=7.3kg$

5 0

3 years ago

Read 2 more answers

Which of the following describes how the current in a circuit can be increased. Select all that apply.

andreyandreev [35.5K]

Answer:
Option B: Increase the voltage, while keeping the resistance constant.

Explanation:
Current is directly proportional to voltage, but indirectly proportional to resistance.

5 0

3 years ago